About 2 weeks ago I started to get a really bad toothache. It was in a tooth that has a filling and is generally very sensitive. Well I took lots of pain killers for it and it went away after about 5 days. I also currently have what I think is a sinus infection. I went to the dentist because I was concerned that it was something with my filling and thought I would need a root canal, but they took x-rays and said that there was no sign of infection and nothing was wrong. I noticed a couple days ago that I have a bump that on the left side of my mouth in my gums on top. It is very sensitive when I touched it or if my mouth is moved in the right way and I noticed today that my tooth is starting to get very sensitive and painful again. Does anyone have any thoughts on this?

Generally if it is sensitive to pressure and it has a big filling on it, its root canal time... sinus infection usually won't cause an intra-oral bump... go back to the dentist

And show him the bump!

If the bump is filled with fluid (pus) you definitely have an abscess. Go back to your dentist and as Amir said, show him the bump.