Symptoms of TMD are facial pain, headaches, jaw clicking, jaw locking, ringing in the ears, tooth pain, neck or shoulder pain, facial tingling or teeth grinding. There are many causes of TMD including arthritis in the joint, whiplash, sports injuries, stress, a blow to the head, orthodontics, poor posture, and habits such as chewing gum or nail biting. Any of these can damage the structures of the jaw joint causing pain, and if the disc is damaged this can lead to clicking or locking of the jaw.