[HayZee518]

evidently your house is shifting. could be the nailing on the studs and jack studs wasn't done properly and the door casing is opening up (shrinking) what you need to do is remove the door moulding (on the sides) and check for "plumb" cut the existing nails that hold the casing in and apply shims between the casing and door opening stud(s) then drive home finishing nails through the shim and door opening studs. finishing nails come in 3 1/2 and 4 inches long. once you moved the casing so the door closes and stays closed, counter sink the nail heads and use a matching stain pen to fill the holes.