About 50% of women experience low back pain during pregnancy. Some studies have suggested women who have experienced back pain before pregnancy are at a higher risk of having back pain during pregnancy. It may be severe enough to cause significant pain and disability in up to a third of pregnant women. Back pain typically begins at around 18 weeks gestation, and peaks between 24 and 36 weeks gestation. Approximately 16% of women who experienced back pain during pregnancy report continued back pain years after pregnancy, indicating those with significant back pain are at greater risk of back pain following pregnancy.

Biomechanical factors of pregnancy shown to be associated with back pain include increased curvature of the lower back, or lumbar lordosis, to support the added weight on the abdomen. Also, a hormone called relaxin is released during pregnancy that softens the structural tissues in the pelvis and lower back to prepare for vaginal delivery. This softening and increased flexibility of the ligaments and joints in the lower back can result in pain. Back pain in pregnancy is often accompanied by radicular symptoms, suggested to be caused by the fetus pressing on the sacral plexus and lumbar plexus in the pelvis.

Typical factors aggravating the back pain of pregnancy include standing, sitting, forward bending, lifting, and walking. Back pain in pregnancy may also be characterized by pain radiating into the thigh and buttocks, night-time pain severe enough to wake the patient, pain that is increased during the night-time, or pain that is increased during the day-time.

Local heat, acetaminophen (paracetamol), and massage can be used to help relieve the pain. Avoiding standing for prolonged periods of time is also suggested.

There is moderate quality evidence that suggests the combination of education and exercise may reduce an individual's risk of developing an episode of low back pain. Lesser quality evidence points to exercise alone as a possible deterrent to the risk of the onset of this condition.

Overall, the outcome for acute low back pain is positive. Pain and disability usually improve a great deal in the first six weeks, with complete recovery reported by 40 to 90%. In those who still have symptoms after six weeks, improvement is generally slower with only small gains up to one year. At one year, pain and disability levels are low to minimal in most people. Distress, previous low back pain, and job satisfaction are predictors of long-term outcome after an episode of acute pain. Certain psychological problems such as depression, or unhappiness due to loss of employment may prolong the episode of low back pain. Following a first episode of back pain, recurrences occur in more than half of people.

For persistent low back pain, the short-term outcome is also positive, with improvement in the first six weeks but very little improvement after that. At one year, those with chronic low back pain usually continue to have moderate pain and disability. People at higher risk of long-term disability include those with poor coping skills or with fear of activity (2.5 times more likely to have poor outcomes at one year), those with a poor ability to cope with pain, functional impairments, poor general health, or a significant psychiatric or psychological component to the pain (Waddell's signs).

Low back pain that lasts at least one day and limits activity is a common complaint. Globally, about 40% of people have LBP at some point in their lives, with estimates as high as 80% of people in the developed world. Approximately 9 to 12% of people (632 million) have LBP at any given point in time, and nearly one quarter (23.2%) report having it at some point over any one-month period. Difficulty most often begins between 20 and 40 years of age. Low back pain is more common among people aged 4080years, with the overall number of individuals affected expected to increase as the population ages.

It is not clear whether men or women have higher rates of low back pain. A 2012 review reported a rate of 9.6% among males and 8.7% among females. Another 2012 review found a higher rate in females than males, which the reviewers felt was possibly due to greater rates of pains due to osteoporosis, menstruation, and pregnancy among women, or possibly because women were more willing to report pain than men. An estimated 70% of women experience back pain during pregnancy with the rate being higher the further along in pregnancy. Current smokers – and especially those who are adolescents – are more likely to have low back pain than former smokers, and former smokers are more likely to have low back pain than those who have never smoked.

People vary in their tendency to get MSDs. Gender is a factor with a higher rate in women than men. Obesity is also a factor, with overweight individuals having a higher risk of some MSDs, specifically lower back.

The most common causes of upper back pain are unknown but theorized to originate from muscular irritation, intervertebral discs, spinal facet joints, ribs or soft tissue (e.g. ligament/fascia) problems. Commonly intra-scapular pain is referred from the lower cervical spine. Contributing factors to injury include; lack of strength, poor posture, overuse injuries (such as repetitive motion), or a trauma (such as a car accident or sports injury). Often thoracic pain can be aggravated twisting, side bending and with prolonged bent spinal postures.

A compression fracture of the vertebra can also cause acute and/or chronic pain in the upper back. Trauma may cause a fracture, but in women over age 50 without significant trauma or someone known to have osteoporosis, a spontaneous vertebral compression fracture is possible.

Other, less common causes of thoracic back pain include a spinal disc herniation which often may have radicular pain (wrapping around the ribs associated with numbness and burning pain), spinal tumors and rib fractures may mimic thoracic pain/radicular pain. Other possible sources of referral pain into the thoracic region include visceral organs like: lungs, gallbladder, stomach, liver duodenum, pleura and cardiac.

Middle back pain has long been considered a "red flag" to alert healthcare professionals to the possibility of cancer (metastasis or spread to the spine). This is not a sensitive or specific phenomenon and can therefore not be relied upon in isolation.

There is a growing consensus that psychosocial factors are another cause of some MSDs. Some theories for this causal relationship found by many researchers include increased muscle tension, increased blood and fluid pressure, reduction of growth functions, pain sensitivity reduction, pupil dilation, body remaining at heightened state of sensitivity. Although research findings are inconsistent at this stage, some of the workplace stressors found to be associated with MSDs in the workplace include high job demands, low social support, and overall job strain. Researchers have consistently identified causal relationships between job dissatisfaction and MSDs. For example, improving job satisfaction can reduce 17-69 per cent of work-related back disorders and improving job control can reduce 37-84 per cent of work-related wrist disorders.

Thoracic spinal pain was significantly associated with: concurrent musculoskeletal pain; growth and physical; lifestyle and social; backpack; postural; psychological; and environmental factors. Specific risk factors identified in adolescents included age (being older) and poorer mental health.

Back strain occurs more in women than men and is more common after pregnancy. Lean people, those standing for long hours and those doing sedentary work in bad posture are prone to back strain. Back strain is also more common in people with excessive curving of the back, weak muscles (as in muscular dystrophies) and tight thigh muscles. Sportspersons who play sports involving lifting heavy weights, pushing and pulling are also prone to back strain.

The diagnosis of mild back strain can be made with a medical history and physical examination. In case of more severe strains, an X-ray should be taken to rule out fracture and disc herniation. Back sprain is treated using analgesics such as ibuprofen, rest and use of ice packs. The patient can resume activities 24-48 hours after pain and swelling is reduced. It is not recommended to have prolonged immobilization or bed rest. If the pain does not subside in two weeks, additional treatment may be required.

Prevention of back strain is possible by adopting proper body mechanics while sitting, standing and lifting. Cessation of smoking, maintaining a healthy diet, exercise and normal weight is also good for preventing back strain.

Like many other joints throughout the human body, facets can experience natural degeneration from constant use. Over time, the cartilage within the joints can naturally begin to wear out, allowing it to become thin or disappear entirely which, in turn, allows the conjoining vertebrae to rub directly against one another with little or no lubricant or separation. A result of this rubbing is often swelling, inflammation or other painful symptoms.

Over time, the body will naturally respond to the instability within the spine by developing bone spurs, thickened ligaments or even cysts that can press up against or pinch the sensitive nerve roots exiting the spinal column.

While primarily caused through natural wear and tear, advanced facet syndrome can also occur as a result of injury to the spine, degenerative disease or lifestyle choices. These causes can include:

- An unexpected, traumatic event such as a car accident, significant fall or high impact sports injury.

- Osteoarthritis

- Spondylolisthesis

- Obesity

- Smoking

- Malnutrition

- Lack of physical exercise or daily activity

Most often the radiculopathy found in the patients are located in the cervical spine, most commonly affecting C6-C8 spinal nerves.

Certain injuries can also lead to radiculopathy. These injuries include lifting heavy objects improperly or suffering from a minor trauma such as a car accident. Less common causes of radiculopathy include injury caused by tumor (which can compress nerve roots locally) and diabetes (which can effectively cause ischemia or lack of blood flow to nerves).

55% of facet syndrome cases occur in cervical vertebrae, and 31% in lumbar. Facet syndrome can progress to spinal osteoarthritis, which is known as spondylosis. Pathology of the C1-C2 (atlantoaxial) joint, the most mobile of all vertebral segments, accounts for 4% of all spondylosis.

Psychogenic pain, also called psychalgia, is physical pain that is caused, increased, or prolonged by mental, emotional, or behavioral factors.

Headache, back pain, or stomach pain are some of the most common types of psychogenic pain. It may occur, rarely, in persons with a mental disorder, but more commonly it accompanies or is induced by social rejection, broken heart, grief, lovesickness, or other such emotional events.

Sufferers are often stigmatized, because both medical professionals and the general public tend to think that pain from psychological source is not "real". However, specialists consider that it is no less actual or hurtful than pain from other sources.

The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, "or described in terms of such damage"" (emphasis added). In the note accompanying that definition, the following can be found about pain that happens for psychological reasons:

Many people report pain in the absence of tissue damage or any likely pathophysiological cause; usually this happens for psychological reasons. There is usually no way to distinguish their experience from that due to tissue damage if we take the subjective report. If they regard their experience as pain and if they report it in the same ways as pain caused by tissue damage, it should be accepted as pain.

Medicine refers also to psychogenic pain or psychalgia as a form of chronic pain under the name of "persistent somatoform pain disorder" or "functional pain syndrome". Causes may be linked to stress, unexpressed emotional conflicts, psychosocial problems, or various mental disorders. Some specialists believe that psychogenic chronic pain exists as a protective distraction to keep dangerous repressed emotions such as anger or rage unconscious.

It remains controversial, however, that chronic pain might arise purely from emotional causes. Treatment may include psychotherapy, antidepressants, analgesics, and other remedies that are used for chronic pain in general.

There are many causes of TOS. The most frequent cause is trauma, either sudden (as in a clavicle fracture caused by a car accident), or repetitive (as in a legal secretary who works with his/her hands, wrists, and arms at a fast paced desk station with non-ergonomic posture for many years). TOS is also found in certain occupations involving lots of lifting of the arms and repetitive use of the wrists and arms.

One cause of arterial compression is trauma, and a recent case involving fracture of the clavicle has been reported.

The two groups of people most likely to develop TOS are those suffering from neck injuries due to traffic accidents and those who use computers in non-ergonomic postures for extended periods of time. TOS is frequently a repetitive stress injury (RSI) caused by certain types of work environments. Other groups which may develop TOS are athletes who frequently raise their arms above the head (such as swimmers, volleyball players, dancers, badminton players, baseball pitchers, and weightlifters), rock climbers, electricians who work long hours with their hands above their heads, and some musicians.

Radiculopathy is a mechanical compression of a nerve root usually at the exit foramen or lateral recess. It may be secondary to degenerative disc disease, osteoarthritis, facet joint degeneration/hypertrophy, ligamentous hypertrophy, spondylolisthesis, or a combination of these factors. Rarer causes of radiculopathy may include radiation, diabetes mellitus, neoplastic disease, or any meningeal-based disease process. Second-stage Lyme meningitis resembles aseptic meningitis and is often associated with radiculopathies.

The cause of spondylolysis remains unknown, however many factors are thought to contribute to its development. The condition is present in up to 6% of the population, majority of which usually present asymptomatically. Research supports that there are hereditary and acquired risk factors that can make one more susceptible to the defect. The disorder is generally more prevalent in males compared to females, and tends to occur earlier in males due to their involvement in more strenuous activities at a younger age. In a young athlete, the spine is still growing which means there are many ossification centers, leaving points of weakness in the spine. This leaves young athletes at increased risk, particularly when involved in repetitive hyperextension and rotation across the lumbar spine. Spondylolysis is a common cause of low back pain in preadolescents and adolescent athletes, as it accounts for about 50% of all low back pain. It is believed that both repetitive trauma and an inherent genetic weakness can make an individual more susceptible to spondylolysis.

Radicular pain, or radiculitis, is pain "radiated" along the dermatome (sensory distribution) of a nerve due to inflammation or other irritation of the nerve root (radiculopathy) at its connection to the spinal column. A common form of radiculitis is sciatica – radicular pain that radiates along the sciatic nerve from the lower spine to the lower back, gluteal muscles, back of the upper thigh, calf, and foot as often secondary to nerve root irritation from a spinal disc herniation or from osteophytes in the lumbar region of the spine.

Surgery may be useful in those with a herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. Discectomy has better outcomes at one year but not at four to ten years. The less invasive microdiscectomy has not been shown to result in a significantly different outcome than regular discectomy with respect to pain. It might however have less risk of infection.

The presence of cauda equina syndrome (in which there is incontinence, weakness and genital numbness) is considered a medical emergency requiring immediate attention and possibly surgical decompression. Regarding the role of surgery for failed medical therapy in people without a significant neurological deficit, a Cochrane review concluded that "limited evidence is now available to support some aspects of surgical practice".

Most cases of back pain are related to issues in human musculoskeletal system and are not related to severe diseases. Musculoskeletal problems also called mechanical because many of them linked to vertebrae physical motions. Back pain itself is not considered a diagnosis, but rather a symptom of underlying (in most cases musculoskeletal) problems.

following:

- Vertebrae misalignment, which can cause nerve interference (also called subluxation), muscle tension, or muscle spasm

- Strained muscles

- Sprained ligaments

- Ruptured disks, which also called "slipped", or herniated disks

- Degenerative discs (lose their cushioning ability). The degeneration usually caused by repetitive strain, or injury, or aging.

- Irritated joints

Electroanalgesia is a form of analgesia, or pain relief, that uses electricity to ease pain. Electrical devices can be internal or external, at the site of pain (local) or delocalized throughout the whole body. It works by interfering with the electric currents of pain signals, inhibiting them from reaching the brain and inducing a response; different from traditional analgesics, such as opiates which mimic natural endorphins and NSAIDS (non-steroidal anti-inflammatory drugs) that help relieve inflammation and stop pain at the source. Electroanalgesia has a lower addictive potential and poses less health threats to the general public, but can cause serious health problems, even death, in people with other electrical devices such as pacemakers or internal hearing aids, or with heart problems.

Sports involving repetitive or forceful hyperextension of the spine, especially when combined with rotation are the main mechanism of injury for spondylolysis. The stress fracture of the pars interarticularis occurs on the side opposite to activity. For instance, for a right-handed player, the fracture occurs on the left side of the vertebrae.

Spondylolysis has a higher occurrence in the following activities:

- Baseball

- Tennis

- Diving

- Cheerleading

- Gymnastics

- Football

- Soccer

- Wrestling

- Weightlifting

- Roller Derby

- Cricket

- Pole Vault

- Rugby

- Volleyball

- Gym

- Ultimate Frisbee (especially during impact from laying out)

Although this condition can be caused by repetitive trauma to the lumbar spine in strenuous sports, other risk factors can also predispose individuals to spondylolsis. Males are more commonly affected by spondylolysis than females. In one study looking at youth athletes, it was found that the mean age of individuals with spondylolisthesis was 20 years of age. Spondylolysis also runs in families suggesting a hereditary component such as a predisposition to weaker vertebrae.

Disc herniation can occur in any disc in the spine, but the two most common forms are lumbar disc herniation and cervical disc herniation. The former is the most common, causing lower back pain (lumbago) and often leg pain as well, in which case it is commonly referred to as sciatica. Lumbar disc herniation occurs 15 times more often than cervical (neck) disc herniation, and it is one of the most common causes of lower back pain. The cervical discs are affected 8% of the time and the upper-to-mid-back (thoracic) discs only 1–2% of the time.

The following locations have no discs and are therefore exempt from the risk of disc herniation: the upper two cervical intervertebral spaces, the sacrum, and the coccyx. Most disc herniations occur when a person is in their thirties or forties when the nucleus pulposus is still a gelatin-like substance. With age the nucleus pulposus changes ("dries out") and the risk of herniation is greatly reduced. After age 50 or 60, osteoarthritic degeneration (spondylosis) or spinal stenosis are more likely causes of low back pain or leg pain.

- 4.8% males and 2.5% females older than 35 experience sciatica during their lifetime.

- Of all individuals, 60% to 80% experience back pain during their lifetime.

- In 14%, pain lasts more than 2 weeks.

- Generally, males have a slightly higher incidence than females.

For most women, PGP resolves in weeks after delivery but for some it can last for years resulting in a reduced tolerance for weight bearing activities. PGP can take from 11 weeks, 6 months or even up to 2 years postpartum to subside. However, some research supports that the average time to complete recovery is 6.25 years, and the more severe the case is, the longer recovery period.

Overall, about 45% of all pregnant women and 25% of all women postpartum suffer from PGP. During pregnancy, serious pain occurs in about 25%, and severe disability in about 8% of patients. After pregnancy, problems are serious in about 7%. There is no correlation between age, culture, nationality and numbers of pregnancies that determine a higher incidence of PGP.

If a woman experiences PGP during one pregnancy, she is more likely to experience it in subsequent pregnancies; but the severity cannot be determined.

Physicians, Nurse Practitioners, Physician Assistants, Nurses and Midwives will typically ask for the need of relief. Women in labor have many pain relief options that work well and pose small risks when given by a trained and experienced clinician. Clinicians also can use different methods for pain relief at different stages of labor. Still, not all options are available at every hospital and birthing center. Depending on the health history of the mother, the presence of allergies or other concerns, some choices will work better than others.

There are many methods of relieving pain used for labor. Rare and unpredictable, serious complications sometimes occur. Also, most medicines used to manage pain during labor pass freely into the placenta to the baby. Asking questions about the procedures and medications might affect the baby are valid questions.