Myofascial pain dysfunction (MPD) is a syndrome of pain caused by spasm in the muscles. Symptoms of a spasm are aching, burning, or stabbing pain, and they may occur in a different part of the body than where the muscle is in spasm (referred pain).

Grinding or clenching the teeth, often associated with stress and tension, is a common cause of spasms in the jaw area (temporomandibular joint), which can cause a tension headache.

Myofascial pain dysfunction may be treated with massage, physical therapy, and medicine.