Silver filled tooth hurts when in contact with metal, why?

The phenomenon : Of different metals contacting each other in the mouth occurs for many people. This is a galvanic reaction recognized by many. No real problem but annoying. Consult w your dentist about the silver filling and discuss your options to replace it if needed.

Galvanic response: Dissimilar metals (filling and fork), when in the presence of salts (saliva) can result in a transfer of ions, producing a small electrical transfer... Thus the toothache. A battery, in other words.