Emotional stress is a common cause of bad habits that aggravate the joint. Bad habits such as clenching or grinding of one’s teeth, biting nails or lip, chewing gum, etc., or other nervous mouth movements, overwork muscles that support the TMJ causing an increase in muscle pain. Any stress of an already misaligned TMJ results in further muscle tension, which usually escalates into a chronic muscle spasm (overactive muscle) and an increase in pain.