Upper Body Imbalance, Help

I am trying to figure out how to address an imbalance I have in my upper body… between the left and right, basically from shoulder to trap.

It isn’t so much of a ‘physique’ concern as it is a physical concern for me.

I first noticed it about a year ago doing rack pulls (the rack is in front of a mirror).

When I deadlift, sometimes I have a hard time keeping the bar straight when lowering it (mostly lighter sets, or higher rep sets). I pull sumo BTW.

When I do unilateral movements, I have to start with my left side. Otherwise, I would end up doing more work for the right.

How do you tell if the problem is just a muscle imbalance? That just one side is a little stronger than the other? Or that the problem could be deeper… such as shoulder misalignment, or something I probably couldn’t correct on my own.