(MPS) is a is a painful musculoskeletal condition, a common cause of musculoskeletal pain. MPS is characterized by the development of Myofascial trigger points (TrPs) that are locally tender when active, and refer pain through specific patterns to other areas of the body. A trigger point or sensitive, painful area in the muscle or the junction of the muscle and fascia (hence, myofascial pain) develops due to any number of causes. Trigger points are usually associated with a taut band, a ropey thickening of the muscle tissue. Typically a trigger point, when pressed upon, will cause the pain to be felt elsewhere. This is what is considered "referred pain".
These factors can cause trigger points: 1. Sudden trauma to musculoskeletal tissues (muscles, ligaments, tendons, bursae). 2. Injury to intervertebral discs. 3. Generalize fatigue (fibromyalgia is a perpetuating factor of MPS, perhaps chronic fatigue syndrome may produce trigger points as well) 4. Repetative motions; Excessive exercise; Muscle strain due to over activity 5. Systemic conditions (eg, gall bladder inflammation, heart attack, appendicitis, stomach irritation) 6. Lack of activity (eg, a broken arm in a sling) 7. Nutritional deficiencies 8. Hormonal changes (eg, trigger point development during PMS or menopause) 9. Nervous tension or stress 10. Chilling of areas of the body (eg, sitting under an air conditioning duct; sleeping in front of an air conditioner).
   The fascia is a tough connective tissue which spreads throughout the body in a three dimensional web from head to foot without interruption. The fascia surrounds every muscle, bone, nerve, blood vessel and organ of the body, all the way down to the cellular level. Therefore, malfunction of the fascial system due to trauma, posture, or inflammation can create a binding down of the fascia, resulting in abnormal pressure on nerves, muscles, bones or organs. This can create pain or malfunction throughout the body, sometimes with bizarre side effects and seemingly unrelated symptoms. It is thought that an extremely high percentage of people suffering with pain and/or lack of motion may be having myofascial problems; but most go undiagnosed, as the importance of fascia is just now being recognized. Many of the standard tests, such as x-rays, myelograms, CAT scans, eletromyography, etc., do not show the fascia. (John Barnes, P.T., 1992).

   Occassionally, trigger points produce autonomic nervous system changes such as flushing of the skin, hypersensitivity of areas of the skin, sweating in areas, or even "goose bumps."  The trigger points cause localized pain, although TrPs can involve the whole body. In three studies, the prevalence of myofascial TrPs among patients complaining of pain anywhere in the body ranged from 30% to 93%; (among patients with chronic craniofacial pain, 55%; and for lumbogluteal pain, 21%.) The characteristic electrical activity of myofascial TrPs most likely originates at dysfunctional endplates of extrafusal muscle fibers. This dysfunction appears to play a key role in the pathophysiology of TrPs. (Simons 1996).  Subjective shortness of breath can be part of the myofascial pain syndrome of the levator scapulae muscle. In one study, 75 patients who reported neck pain & shortness of breath were examined. Trigger points were located and inactivated with acupuncture needles (dry needling). 68 of the 75 patients in the study reported that their shortness of breath and soreness were abolished immediately after inactivation of the TrPs. The other 7 patients needed a second trial of inactivation. Eliminating the trigger points eliminated the symptoms. (Journal of Muskuloskeletal Pain, 1996).