Freeing a Sticking Door

Doors stick when the hinges sag, when the door frame shifts, or when humidity causes the door and door frame to swell. If the door seems to be sagging within the frame, make sure the hinge screws are tight. Screws that are loose may need to have their screw holes repaired.
If the door continues to stick, you'll need to plane or sand the door edge at the point where the door touches