It could possibly be a sensitivity to the amalgam fillings. You may have an allergy to the material which is very rare. You should consult your dentist and possibly consider removing the amalgams if no other cause can be found for the symptoms you have described. He/she may replace the fillings with something temporary and see how the area responds. If it gets better, you may need to get "white" fillings instead of amalgam ones.
Mercury + Brain + organs = damage