Reflex sympathetic dystrophy (RSD) is a condition that follows injury to an arm or leg. RSD is also known as causalgia and sympathetic dystrophy. The extremity is painful, diffusely swollen, tender to the touch, and weak. Often trophic skin changes (for example, hyperhidrosis) accompany the pain and swelling, and the extremity may be excessively hot or cold. The syndrome is caused by abnormal nerve impulses after injury arising in the network of nerves known as the sympathetic nerve system. The sympathetic nerve system regulates blood flow and temperature sensation. In addition, special sympathetic nerves carry pain signals. After some injuries, the sympathetic nerve system may be activated inappropriately and cause decreased blood flow with increased pain. This pain is typically burning and severe.

Myofascial pain syndrome (MPS) describes a chronic nondegenerative, noninflammatory musculoskeletal pain condition. Distinct areas within muscles or their delicate connective tissue coverings (fascia) become abnormally thickened and tight. When the myofascial tissues tighten and lose their elasticity, neurotransmitter ability to send and receive messages between the brain and body is damaged. These areas of thick, ropelike bands of fascia are called trigger points, and they can cause pain long after a muscle injury should have healed. Trigger points refer pain both locally and distantly. Each trigger point can develop satellite and secondary trigger points. Tender trigger points cause symptoms that vary from mild discomfort to incapacitating pain. Symptoms include muscle stiffness and aching and sharp shooting pains or tingling and numbness in areas distant from the trigger point. The discomfort may cause sleep disturbance, fatigue, and depression. Most commonly trigger points are in the neck, back or buttocks.

Fibromyalgia syndrome (FMS) is a chronic central nervous system, neuroendocrine, non-degenerative, non-inflammatory, pain amplification disorder. It is systemic and biochemical in nature. It is responsible for diffuse body-wide pain, tender points that hurt but don't refer pain, and sleep disturbances. Lab tests for FMS are valid only to rule out other conditions. No blood test can accurately identify FMS. Fibromyalgia syndrome was first described by William Balfour, a surgeon at the University of Edinburgh, in 1816. Since then, the medical profession has called it many different names, including chronic rheumatism, myalgia, pressure point syndrome, and fibrositis.

The official definition requires that tender points must be present in all four quadrants of the body accompanied by widespread, continuous pain for at least three months. Tender points occur in pairs on various parts of the body. Because they occur in pairs, the pain is usually distributed equally on both sides of the body.

In traumatic FMS, tender points are often clustered around an injury. These clusters can also occur around a repetitive strain or a degenerative and/or inflammatory problem, such as arthritis.

Costochondritis (Tietze's syndrome) is painful inflammation of the cartilage that attaches the ribs to the sternum. It most commonly affects the 3rd or 4th ribs and may mimic cardiac pain. Symptoms include chest tightness, sharp chest wall pain with radiation into the arm, and increased pain with movement. Onset of the syndrome is generally before age 40 and both men and women are equally affected. Usually the cause of the inflammation is unknown, however it can arise from a chest injury, respiratory infection, or unusual strenuous physical activity.

For most people, costochondritis lasts from six months to a year; however, for some people it remains a chronic condition.

Chronic low back pain accounts for billions of healthcare dollars each year. Eight out of ten people will have a problem with back pain at some time during their lives. Back pain is more likely to occur during the ages of 30 to 50, the most productive period of most people's lives. While most episodes of low back pain are self-limited, for some people these episodes of back pain become chronic. Many etiologies for chronic back pain exist. Some of the most common include obesity and physical deconditioning, spinal injury, nerve root compression, and intervertebral disk degeneration.

Occipital neuralgia is characterized by pain in the cervical and posterior regions of the head which may or may not radiate into the sides of the head and into the facial and frontal regions. The occipital nerves enter the scalp over the back of the skull and transmit sensation from a large portion of the scalp. Patients complain of severe headache over the back, top, and sides of the scalp. The headache may be described as "burning, stabbing, tingling, or electric" in nature. There may also be loss of sensation or numbness over the painful area. Commonly referred to as “tension Headache”.

Trigeminal neuralgia is a disorder of the trigeminal, or fifth cranial nerve. Another common name for trigeminal neuralgia is tic douloureux . The chief characteristic is sharp electrical pain which lasts for seconds. This pain is triggered by touching a specific area of the skin.

Cervicogenic headaches are headaches due to nerve pathology in the back of the neck in the cervical spine area. The upper nerves of the neck and the trigeminal nerve in the face are on the same pathway to the brain. The trigeminal nerve is responsible for the perception of pain in the head. This connection explains why a cervical nerve disorder can exhibit headache as a primary symptom. Many patients who are diagnosed with cervicogenic headache have the traditional symptoms of tension headache. In addition, many patients who have positive tests for cervicogenic headache may also have the symptoms of migraine and cluster headache.