Shimming the middle hinge, you are trying to bend the door sideways, All that has done is stress the screws on the other two hinges.
You found a warp in the frame if the gap between the door and the jam, that is fixable and may have happened if someone tried to improve security.
Newer rules require screws in the strike plate to reach the stud in the wall behind the jam. If some one did that they may have tighten them too much and pulled the jam away from the door.
The fix would be to remove the trim on the inside and shim the jam back out where the gap would be equal. If the longer screws are not there install those while you are at it and change one screw on each hinge to a longer one while you are at it.
Use a box cutter knife to cut the paint and caulk on both sides of the trim, use a small flat bar to pry the trim off. pull the nails thru the trim with pliers and you won't damage the wood.