tooth sensitivity with temporary and permanent crown after root canal

I had a root canal after a cavity on tooth #29 reached the nerve.  I didn't experience any pain or sensitivity before the root canal, but after with the temporary crown, the tooth was extremely sensitive to temperature and chewing.  I had hoped that the permanent crown would help this, but so far I am experiencing the same sensitivity.  My dentist has checked my bite and the margins and says that they both look good. The gums around the tooth look slightly red and irritated, though my dentist atttributed this to the crown fitting (yesterday).  Any ideas as to why I'm still in pain?  Many thanks in advance for your help.

[scottma]

The sensitivity may come from occlusal interfernce of new crown or periapical inflammation of post root canal obturation.