On one hand, I do think it takes a molar a while longer to recover from the root canal. I remember that mine felt weird for about a month afterwards. Ever since it was done I would have an occasional twinge of pain when eating, or with cold foods... but it didn't give me major problems until after a year later.
That is when it abscessed because one canal wasn't filled all the way down to the bottom. After having endodontic surgery done to fix that, the pain continued. So I had the root-canal retreated. Turned out I had a tear-drop shaped canal, and it was cleaned and filled as if it was a round canal, meaning there was one little "wing" of canal left untreated. The regular dentist couldn't see it. It took an endodontist with their mega-microscopes to be able to see it.
It has been a month now since the retreatment and the tooth feel good. For you I'd say give it a month, and if it keeps bothering you, then get it looked at by an endodontist.