This may\may not be normal and may subside in 1 day, two days, or longer. The full answer if far beyond the scope of this type of forum. It is not uncommon to have some post operative discomfort or sensitivity following a new filling.
Basically if it's not too bad, wait it out a few days. If it gets worse or doesn't go away within that time frame, call your dentist and ask what he\she suggests.