yeah, I agree with Blue Fedora. Sounds like you need a root canal. This happened to me recently we replaced an old cracked crown (that wasn't bothering me a BIT!) they put the temp on and my tooth just started throbbing, day and not. Not badly, but always there. The Dentist said this happens sometimes and the only cure is to kill that nerve.

I get a kick out of root canals. I have a cute young endodontist, he uses all kinds of really strange tiny saws and things, there's no pain at all... it's not like it used to be..