Why do I have jaw pain and clicking?

TMD. The most common cause of jaw pain with clicking is what is known as temporo-mandibular disorder. The differential diagnosis includes true inflammation (arthritis) of the jaw joint or masticatory (muscles that close the jaw) muscle spasm as in grinding your teeth as a habit. The diagnosis can be resolved by a dentist or oral surgeon. Ent docs see this commonly as otalgia (ear ache).
Probably TMJ. "clicking" when opening or closing is caused by trauma or damage to the tmj, temporomandibular joint. If you have pain in the morning you are probably clenching or grinding during sleep, which is common. Your dentist can make a custom fitted anti bruxism appliance, commonly known as a night guard. Also many chiropractors can do adjustments that relieve pain associated with the tmj.
Jaw Joint. Jaw Joint (TMJ) problem. Complex problem. See TMJ expert . Any dentist can be a TMJ expert with the proper training and experience. Most commonly, oral surgeons, prosthodontists, and orofacial pain specialists. Ask your MD, your dentist and your dental society for referrals. Very rarely requires TMJ surgery.
History & duration?? Clicking of the jaw signals a tmj/tmd condition, with articular disk being displaced forward. The pain can come from the jaw joint/joints being out of alignment. You should see a dentist and/or a TMJ specialist before it gets worse and becomes unmanageable.