@umbra21 - I have the same problem with jaw clenching, but I thought at first that I had some kind of nerve disease or a problem with my teeth, because the pain didn't seem to have a cause.
I went to the dentist and he told me that I just have a jaw shape that puts a lot of pressure on a particular point. He told me I shouldn't chew gum or I would make it worse and that I was always going to have problems keeping any fillings in good shape.
He wasn't wrong about that. Thank goodness I don't have many fillings, but they always seem to crack or fall out within a couple of years. It's very expensive although it doesn't tend to be painful on my teeth. I do still sometimes get the pain in my jaw, but I'm better at relaxing everything now, so it goes away pretty quickly.