1.5 years ago I received a filling on tooth number 3 on the top right. Filling went well however on occasion it would hurt slightly when biting. About 4 months ago I began to have lingering pain that would come and go on a daily basis. My dentist thought it could be grinding, so I bought a mouth guard. That did not help. I received a root canal 3 weeks ago, an ever since, I have still felt the same pain. Also the tooth was extremely sensitive to the touch post-operation, which I had never experienced before in the past 3 root canals I have had. My endodontist prescribed me some antibiotics, which seemed to help the sensitivity slightly but the lingering pain continued. A few days after the medicine was done, the pain remained present and I went back to the endodontist who removed the root canal inserts and disinfected the tooth with material, sealed it back with a temp filling and told me to give it a week. It is 3 days later and I am still in pain, sensitivity to touch is back, and linger pain still there.
Please let me know what you think the problem could be.