Pain in tooth two months after crown

In August, I started feeling sensitivity in my back bottom molar.  I scheduled a dentist appointment and went in September, where he told me that I needed a root canal.  That Friday, he sent me to a root canal specialist.  I had little pain after the root canal.  In early October, I went to the dentist and got my temporary crown.  On October 22, I had my permanent crown put on.  I had no problems with that tooth until about 2 weeks ago.  I slowly started feeling pain in the back of my mouth.  The dentist had x-rayed my other teeth and told me they were fine, so I don't think it is another tooth going bad.  I am pretty sure it is the same tooth causing pain again.  I lost my dental insurance in November, so I can't really afford to go back to the dentist, but I will if the pain gets worse.  Right now it is more of a slight annoying pain, nothing too severe.  Is it normal to still have some sensitivity after a crown is placed?  Could the problem be the crown is not the right fit?  He had a hard time fitting mine.

[Jerome Tsang, DDS]

Its possible it may be the fit of the crown but it seems unusual to get pain after awhile and not initially after placement.  You may want to go back to the dentist and let him/her see whats going on.  Its possible the root canal may have a problem as well so going back to the specialist may be another option as well.