Pain 3 months after a crown, already had a root canal.

Had a crown and root canal done several years ago. The crown broke so I got a new one 3 months ago. Everything was fine, no pain, until this weekend then all of the sudden I have extreme pain when biting down and the gums around it are very sensitive. Is it possible the crown can shift or raise up a bit throwing off the bite? Why would it be fine for 3 months then all the sudden start to hurt? How can a tooth that has had a root canal already hurt? Also hurts if I touch it with my finger.