20 year old metal crown hurts when i bite on it: Can it be resurfaced?

Hi:
Unfortunately without xray and exam it is difficult to give you accurate advice.  Generally, pain upon biting can be due to infection, cracked tooth or needing simple bite adjustment.
Best,
Dr. Maddahi

I would recommend seeing your dentist for an evaluation.  Anytime you are having pain with a crown upon biting that isn't a good sign.  Most likely the crown/tooth has been bothered by decay or potentially a crack over the years.  I would recommend an x ray to see your dentist for an evaluation.  It sounds like there may be potential for a root canal but at the very least a bite adjustment.  Your dentist will diagnose the problem and help you fix it!  Good Luck!