I have a really bad sharp pain in my top right side molar.    Also on the opposite side a tooth hurt there as well but just not as bad an not as often.   The pain comes mostly when I am eating. If I bite into something on the wrong side it sends a shooting pain.   I  have not been to the dentist in about two years but at the time I had no cavities.   What can this pain be from?  And how do I get it to stop?

I know I have two cavities but I have been unable to get them fixed due to no money.  I have two kids and lots of bills.  I have no money for extra dental care and the only thing I can get done for free are extractions.  I do not need to pull the teeth.  I only need fillings for them. Where can I go for free dental care for fillings?