I had root canaled my tooth3 months back .but now having sore feeling in the same tooth ..can you please suggest ?

Missed canal?!: If the root canal was done on a molar, it sounds like one of the canal was missed ... Could be other reasons, but this one is most common. Have it checked by an endodontist.

See the dentist: This question is too broad to answer. Has the tooth been restored? If not, it should have been. See the dentist who did the root canal therapy for a check-up. Sometimes root canal problems don't resolve after treatment and may have to be retreated.