Thanks for the responses guys

. Yeah I did get a cleaning at the same time as my xrays. I am hoping it is just sensitivity. I just hate going to my dentist, he is specialist happy. Every time I go in with pain, he refers me for some huge procedure. I absolutely refuse to get a root canal. The first tooth I had a root canal on, is gone and the second one has failed twice!
I just remember having this feeling once before on another tooth and when I got xrays my old dentist said it was a cavity and filled it. That is why I am not hopeful. Also I already have a filling in that tooth, that is why I fear a root canal. Especially because I have yet to have this guy actually do something other than refer me somewhere else. I think that I will tell him that I refuse a root canal until it is absolutely necessary and just tell him to fill it for now and the jerk better listen. Sorry for my ranting, I hate HMO's and I hate my dentist