Tweet. Clicking jaw, also referred to as popping jaw or TMJ (temporomandibular joint) syndrome/dysfunction is a symptom associated with inflammation of the temporomandibular joint or uncoordinated action of the facial muscles.Place your cursor over selected (red outlined) areas for a further explanation of the diagram. ‘Clicking’ sound when opening and closing the mouth. ‘ 2 Popping’ or grinding of the TMJ when opening and closing the mouth. 3  Temporofrontal headaches (headaches of the forehead or temples – refer to image above). 4  Aching pain in or around the ear.