If you have mercury fillings in a cold winter ,

will this affect you more

will you get more tooth pain etc ?

If you have tooth pain you should see a dentist. Old mercury fillings can develop decay under the filling if the fillings no longer make a tight seal.

If you have tooth pain, that is a bad sign. Take care of it before you need a root canal. I have had three root canals. They can be very painful and expensive to treat.

yes, but the metal in winter will expand more will it not ??

causing more pain ??

The weather isn't much of a factor in terms of teeth exposed to temperature changes. More important is not to expose the teeth to large temperature changes, such such eating very hot food then drinking a very cold beverage.