Myofascial pain syndrome (MPS) is a common but misunderstood muscular pain disorder involving pain referred from small, tender trigger points within myofascial structures in or distant from the area of pain. Misdiagnosis or inadequate management of this disorder after onset may lead to development of a complex chronic pain syndrome. A review of the clinical characteristics of 164 patients whose chief complaints led to the diagnosis of MPS revealed that these patients had (1) tenderness at points in firm bands of skeletal muscle that were consistent with past reports, (2) specific patterns of pain referral associated with each trigger point, (3) frequent emotional, postural, and behavioral contributing factors, and (4) frequent associated symptoms and concomitant diagnoses.