Myofascial pain syndrome (MPS) refers to pain and presumed inflammation in the body's soft tissues or muscles. Myofascial pain is a chronic, painful condition that affects the fascia (connective tissue that covers the muscles). Myofascial pain syndrome might involve either a single muscle or a muscle group. In some cases, the area where a person experiences the pain might not be where the myofascial pain generator is located. Experts believe that the actual site of the injury or the strain prompts the development of a trigger point that, in turn, causes pain in other areas. This situation is known as referred pain.