Americans spend approximately $50 billion each year on low back pain, the most common cause of job-related disability and a leading contributor to missed work. Back pain is the second most common neurological ailment in the United States — only headache is more common. Most occurrences of low back pain go away within a few days. Others take much longer to resolve or lead to more serious conditions. Acute or short-term low back pain generally lasts from a few days to a few weeks. Most acute back pain is  the result of trauma to the lower back.   Pain from trauma may be caused by a sports injury, work around the house or in the garden, or a sudden jolt such as a car accident or other stress on spinal bones and tissues. Symptoms may range from muscle ache to shooting or stabbing pain, limited flexibility and/or range of motion, or an inability to stand straight.

Chronic back pain is measured by duration — pain that persists for more than 3 months is considered chronic. It is often progressive.   Pain Management Clinic

• the seven cervical or neck vertebrae (labeled C1–C7), the 12 thoracic or upper back vertebrae (labeled T1–T12), the five lumbar vertebrae (labeled L1–L5), which we know as the lower back, and
• the sacrum and coccyx, a group of bones fused together at the base of the spine.

Pain can occur when, for example, someone lifts something too heavy or overstretches, causing a sprain, strain, or spasm in one of the muscles or ligaments in the back. If the spine becomes overly strained or compressed, a disc may rupture or bulge outward. This rupture may put pressure on one of the more than 50 nerves rooted to the spinal cord that control body movements and transmit signals from the body to the brain. When these nerve roots become compressed or irritated, back pain results.

Most low back pain follows injury or trauma to the back.

Conditions that may cause low back pain and require treatment by a physician or other health specialist include:Bulging disc (also called protruding, herniated, or ruptured disc). The intervertebral discs are under constant pressure. As discs degenerate and weaken, cartilage can bulge or be pushed into the space containing the spinal cord or a nerve root, causing pain. Studies have shown that most herniated discs occur in the lower, lumbar portion of the spinal column. A much more serious complication of a ruptured disc is cauda equina syndrome, which occurs when disc material is pushed into the spinal canal and compresses the bundle of lumbar and sacral nerve roots. Permanent neurological damage may result if this syndrome is left untreated. Sciatica is a condition in which a herniated or ruptured disc presses on the sciatic nerve, the large nerve that extends down the spinal column to its exit point in the pelvis and carries nerve fibers to the leg. This compression causes shock-like or burning low back pain combined with pain through the buttocks and down one leg to below the knee, occasionally reaching the foot. In the most extreme cases, when the nerve is pinched between the disc and an adjacent bone, the symptoms involve not pain but numbness and some loss of motor control over the leg due to interruption of nerve signaling. Spinal stenosis related to congenital narrowing of the bony canal predisposes some people to pain related to disc disease. Osteoporosis is a metabolic bone disease marked by progressive decrease in bone density and strength. Fracture of brittle, porous bones in the spine and hips results when the body fails to produce new bone and/or absorbs too much existing bone. Women are four times more likely than men to develop osteoporosis.

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, and multiple "tender points," particularly in the neck, spine, shoulders, and hips.

Most low back pain can be treated without surgery. Treatment involves using analgesics, reducing inflammation, restoring proper function and strength to the back, and preventing recurrence of the injury. Most patients with back pain recover without residual functional loss. Patients should contact a doctor if there is not a noticeable reduction in pain and inflammation after 72 hours of self-care. Medications are often used to treat acute and chronic low back pain. Effective pain relief may involve a combination of prescription drugs and over-the-counter remedies. Patients should always check with a doctor before taking drugs for pain relief. Over-the-counter analgesics, including nonsteroidal anti-inflammatory drugs (aspirin, naproxen, and ibuprofen), are taken orally to reduce stiffness, swelling, and inflammation and to ease mild to moderate low back pain. Counter-irritants applied topically to the skin as a cream or spray stimulate the nerve endings in the skin to provide feelings of warmth or cold and dull the sense of pain. Topical analgesics can also reduce inflammation and stimulate blood flow. Many of these compounds contain salicylates, the same ingredient found in oral pain medications containing aspirin.

• Anticonvulsants — drugs primarily used to treat seizures — may be useful in treating certain types of nerve pain and may also be prescribed with analgesics. Some antidepressants, particularly tricyclic antidepressants such as amitriptyline and desipramine, have been shown to relieve pain (independent of their effect on depression) and assist with sleep. Antidepressants alter levels of brain chemicals to elevate mood and dull pain signals. Many of the new antidepressants, such as the selective serotonin reuptake inhibitors, are being studied for their effectiveness in pain relief. Opioids such as codeine, oxycodone, hydrocodone, and morphine are often prescribed to manage severe acute and chronic back pain but should be used only for a short period of time and under a physician’s supervision.
• Spinal manipulation is literally a "hands-on" approach in which professionally licensed specialists (doctors of chiropractic care) use leverage and a series of exercises to adjust spinal structures and restore back mobility.

In the most serious cases, when the condition does not respond to other therapies, surgery may relieve pain caused by back problems or serious musculoskeletal injuries. Some surgical procedures may be performed in a doctor's office under local anesthesia, while others require hospitalization. It may be months following surgery before the patient is fully healed, and he or she may suffer permanent loss of flexibility. Since invasive back surgery is not always successful, it should be performed only in patients with progressive neurologic disease or damage to the peripheral nerves.

• Discectomy is one of the more common ways to remove pressure on a nerve root from a bulging disc or bone spur. During the procedure the surgeon takes out a small piece of the lamina (the arched bony roof of the spinal canal) to remove the obstruction below. Foraminotomy is an operation that "cleans out" or enlarges the bony hole (foramen) where a nerve root exits the spinal canal. Bulging discs or joints thickened with age can cause narrowing of the space through which the spinal nerve exits and can press on the nerve, resulting in pain, numbness, and weakness in an arm or leg. Small pieces of bone over the nerve are removed through a small slit, allowing the surgeon to cut away the blockage and relieve the pressure on the nerve. IntraDiscal Electrothermal Therapy (IDET) uses thermal energy to treat pain resulting from a cracked or bulging spinal disc. A special needle is inserted via a catheter into the disc and heated to a high temperature for up to 20 minutes. The heat thickens and seals the disc wall and reduces inner disc bulge and irritation of the spinal nerve. Nucleoplasty uses radiofrequency energy to treat patients with low back pain from contained, or mildly herniated, discs. Guided by x-ray imaging, a wand-like instrument is inserted through a needle into the disc to create a channel that allows inner disc material to be removed. The wand then heats and shrinks the tissue, sealing the disc wall. Several channels are made depending on how much disc material needs to be removed. Radiofrequency lesioning is a procedure using electrical impulses to interrupt nerve conduction (including the conduction of pain signals) for 6 to12 months. Using x-ray guidance, a special needle is inserted into nerve tissue in the affected area. Tissue surrounding the needle tip is heated for 90-120 seconds, resulting in localized destruction of the nerves. Spinal fusion is used to strengthen the spine and prevent painful movements. The spinal disc(s) between two or more vertebrae is removed and the adjacent vertebrae are "fused" by bone grafts and/or metal devices secured by screws. Spinal fusion may result in some loss of flexibility in the spine and requires a long recovery period to allow the bone grafts to grow and fuse the vertebrae together.
• Spinal laminectomy (also known as spinal decompression) involves the removal of the lamina (usually both sides) to increase the size of the spinal canal and relieve pressure on the spinal cord and nerve roots.

Other surgical procedures to relieve severe chronic pain include rhizotomy, in which the nerve root close to where it enters the spinal cord is cut to block nerve transmission and all senses from the area of the body experiencing pain; cordotomy, where bundles of nerve fibers on one or both sides of the spinal cord are intentionally severed to stop the transmission of pain signals to the brain; and dorsal root entry zone operation, or DREZ, in which spinal neurons transmitting the patient’s pain are destroyed surgically.