Pain is caused by the muscles in and around the jaw joint tightening up. Joint noise occurs if the disc of cartilage moves out of its normal position between the bones of the jaw joint. Most commonly, the disc slips forward and a noise is made when it returns to its normal position in between the bones. The noise sounds louder to some patients than others because the joint is just in front of the ear. The ligaments and muscles surrounding the joint can in turn go into spasm, producing pain and a difficulty in opening the mouth properly.