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

I would recommend that you see your dentist for an x-ray and a complete evaluation. There are many things that could be happening to this tooth. A root canal should not hurt. If it does, it usually means that the root canal is failing. The best thing to do is see your dentist as soon as possible. I hope this helps and you can click save under my name if you have more questions you'd like me to answer.

Sorry to hear about your pain.   Is it possible the crown can shift or raise up a bit throwing off the bite? Everything is possible but very unlikely.  The more likely scenario would be that the crown was made too high or that it wasn't properly seated.Why would it be fine for 3 months then all the sudden start to hurt? Infection can take time reach the nerve.How can a tooth that has had a root canal already hurt? A root canal tooth should not hurt.  If it does, then it usually means that your root canal treament failed and that you will need to re-treat your root canal.X-rays and pulp test will be needed to properly diagnose your issue, so I would recommend that you go talk to your dentist about it.

The best solution is to go to your dentist and have an x-ray taken. There are many things that could be happening to this tooth. Without more diagnostic information it's difficult to give you a diagnosis.