Builder's suggestion was my first thought, but since he's covered it so well, try this... back each hinge screw (on the frame face) out about 1/2 inch (assuming they are 1 3/4 inch screws) and spray a little of the WD-40 on the exposed part and re-seat. Additionally, you might try replacing at least one of the screws in each hinge (again, on the frame face) with a bit longer screw. The purpose is to penetrate the finished frame face and secure it to the underlying structure frame. Maybe 2 inches or better...
Luck!