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.