Pain after elective root canal

I have a tooth - my upper right lateral incisor - that has had multiple problems over the years.  When it came in as a child, it had a small nick out of it near the gum line that later became a cavity and I had filled.  Over the years (I'm 38), I had it filled a few times as the filling would wear out.  The last time, there wasn't enough to have it filled, so my dentist put a crown on it - twice (the first one wasn't high enough into the gum so the lines were visible and wearing).  The crown looks great, no problems.  Except that after the second crown, I developed extreme sensitivity in the tooth to cold.  I live in New England - last winter was torturous.  

I switched dentists, he xrayed the tooth, and suggested an elective root canal if I was in that much pain (I was, during fall & winter).  Just had it done Tues, no infection, all went well.  But now the tooth is extremely sensitive to pressure - all of a sudden.  It had been sore the past few days, but this morning I could barely brush it.  

Is that normal after a root canal?  What could be wrong with it?  I'm so tired of all of the issues with this one tooth!

Thanks

[lynn117]

if it is only sensitive to pressure it sounds like it just needs the bite adjusted. this is very easy and should be free.

[CountryMom27]

I can't even brush the tooth.  I called the endo today and he thinks it's infected, particularly since the pain is worse since the RC was done.  

The tooth doesn't hit at all when I bite - but I can't even touch it with my tongue without agony.