Root Canal Problem

Hi,
I was wondering if anyone has had the same problem.... About a year ago I had a root canal done on one of my top molars. The Dentist had alot of difficulty removing the roots. After the procedure I had alot of tenderness and and sensitivity that has never really gone away. I had a porcelin crown put on and was told the sensitivity should go away. Now after a year i have started to have more pain and this week have noticed a pocket of swelling and redness on the gumline of the tooth that had the root canal. I think its absessing!! I should also mention that I have been having severe headaches and also have been to the Dr. 3 times within the last 2 weeks for severe sore throat, sinus infection, and bronchitis, and Im on Antibiotics . Do you think this root canal can be the source of these infections? I should also mention I am very tired and weak. I am calling the Dentist Monday to see if I can get an appt. to have this checked out. Is it possible that a root was missed and I will have to go thru another root canal??? Tweet