Weird, I had this same problem recently. I had a root canal down and a few months later my tooth started hurting again. I was now going to a different dentist and he took out the filling and the previous dentist didn't fill my tooth right and my nerves were swollen so they had to cut the nerves and do a new root canal with a new filling. Good luck and I hope you feel better soon. It is unusual that a tooth would hurt two months after a root canal, although it is not impossible. It might be that the restaurantion done on the tooth is too high, not letting the tooth heal correctly. There are always chances that there was an extra canal that wasn't seen by the operator. You can talk to your dentist about that possibility. He might suggest to wait 6 months.