I got two fillings today and my teeth hurt while brushing them, even if I brush gently. Is this normal? Does anyone know how long the sensitivity lasts?

Give the area a couple of days to settle down to brushing. Depending on how deep the cavities were it could take a few weeks for the sensitivity to go away. If you feel that when you gently close your teeth together that you are touching first where the fillings were done, go back to the dentist and have him/her adjust your bite.

Thanks for contributing your expertise again, the sensitivity seems to be diminishing day by day. I also got Tom's Maximum Strength Sensitive toothpaste to help with that.

Glad to hear things are feeling better :)