TMD, temporomandibular joint disorder, is often referred to as TMJ pain. Pain can happen with opening and closing the mouth. Your jaw may occasionally lock. Most TMJ sufferers have clicking and popping sounds. Pain can also radiate and be described as headaches, ear pain, and pain in the neck, shoulders and upper back also happen as a result of teeth grinding, jaw clenching, and jaw misalignment. Those who complain of TMJ symptoms often feel them the most during times of stress when jaw clenching tends to happen most.