My dentist said it is a pretty rare, but known problem. The best way I can describe my problem is this. Well that is the feeling I have almost all the time. It gets worse with certain load frequencies. I think it may be related to the metal filling.
Some patients actually report being able to pick up radio stations on their fillings.
Sounds like you have a similar problem. The situation stems from the fact that metals are conductive and saliva can act like a wire to connect the two metals or in your case the two or more fillings. Since silver fillings contain several different metals, you only need one filling to create the connection. This information may be more than you wanted to know but the phenomena of galvanic reaction is not harmful to the patient but may accelerate the corrosion of your silver restorations. You don't mention what occurred recently to make it more pronounced.