What could cause sensitive gums two months after a root canal?

Root Canal: If the rct was uneventful then the sensitive gums are most probably due to recession of the tissue exposing root surface that can be very sensitive. If it feels like pressure is building up or the gum tissue under the rct tooth is sensitive to biting or touch then you need to see the treating dentist to evaluate the issue.

Still infected?: If you are still having pain or sensitivity this long after a root canal...It may be reinfected. The root canal is done only to remove the nerve tissue from inside the tooth. It is then filled to take the place of the removed nerve tissue. So...You may still have a small infection at the root tips of the tooth. Go back to the doctor..It may just need another round of antibiotics.