Welcome to the Forum, if it was mine l would be doing a little more investigating,
First l would put the car up on stands and take the wheels off, then get a straight edge and place it against the outer side of the brake drum, maybe put a couple of wheel nuts back on to hold the drum in place , then measure back to a particular point to the body, (inside the wheel well ) do both sides for a comparison and make sure to measure to the same point, this should give you an idea as to whether the diff is sitting central to the body or you may have panel issues, try this as a start and post your results, good luck, Andrew..,