How much does it cost get get a dental crown adjusted?

If the issue is a simple bite adjustment then I would think there would be a nominal fee at most, usually this is just complimentary, especially if we did the crown.  However, there maybe underlying issues with the tooth such as re-infection, periodontal issues or feature.  I would return to your dentist and have him/her evaluate the situation to make sure to resolve the issue. 

If your crown has been symptom free for two years, there is a possibility there is an issue with the root canal and not the bite on the crown.  The entire situation should be evaluated.  It is possible that adjusting the crown bite may be all that is needed.  Cost would be up to the individual doctor, but you minimally need an xray and exam of that tooth.