I will tell you, I clench my jaw constantly, and don't even realize I am doing it. I have the same issues, my jaw
is always sore
. I try to catch myself clenching, and stop, but like I said, most of the time, I don't even realize I am doing it. This can cause ear aches, headaches, pain when chewing, it can wreak havoc on your teeth! My jaw gets extremely tired when I chew things like steak or gum. Try to be aware of it, and see if you can notice when you are doing it.
Good Luck to you!