hello and welcome to HCM forum,
first of all i would like to inform you that as i cannot check your tooth clinically , therefore won't be able to confirm that whether the filling has dislodged or it has fractured due to which irritants are seeping in and causing sensitivity and pain.
you have not mentioned about the nature of pain or sensitivity and does it radiate or is it localized, anyways, there is something wrong with the filling due to which you are facing problem,therefore i would suggest you to visit your dentist
soon and get the filling replaced before its get late.
i wish you good health,