Why do I have a bad click on one side of my jaw and how can it be fixed?

Sometimes this is painfully and on rare occasions it even locks momentarily before unlocking again with a snap. This happens mostly if I sleep with the damaged (“clicky”) side pressed against my pillow.

I have heard that clicking jaws are quite common, but what about when this causes occasional locking and ache? Is it possible that teeth grinding could be playing a part? I don’t know if I do it or not.

Some mornings I wake up and it is painful but most mornings it is fine, although the click is always there.