I have been having lower jaw pain off and on i feel like i got punched when the pain is there its hard to move jaw.& when pain is gone feels better?

That's very simple: Pain indicates a problem. That's nature's way of telling us to see a doctor in order to diagnose the problem and treat it. We can't diagnose problems such as these without actually examining you and seeing x-rays of the area in question. The sooner you see a dentist, the sooner you will feel better. It won't go away by itself. In fact, it's likely to get worse very quickly!

Jaw and Muscle Pain: It appears that you have a serious TMJ and muscle dysfunction that causes these muscles to go into a spasm and the jaw joint (TMJ) to lock when you are in a closed position. You seriously need treatment from a dentist that is very skilled at treating tmj. Only about 5% of dentist are really good in this realm.