I'd like to see a pic of the front view of the frame with the bumper off. Also put a straight edge vertically along the frame and compare it to the side to side angle on the shackles. Might have a little frame twist right at the mount. IF it's mostly at the mount, pull the frame bushing, get a solid steel bar the size of the bushing's inside and use it for leverage to bend it back up.
Are both sides the same or mostly the drivers side?