The body is assymmetric in many ways; one of the big issues competing bodybuilders face besides trying to put on the muscle and make it look good. Symmetry is often a judging criteria.
It's quite normal to have a natural imbalance like one shoulder sitting higher than the other. If it's because of a concurrent injury, then that's a different story. But if your technique is symmetrical, with no weaknesses on one side, or chronic injury on one side, I wouldn't worry about it.
My brother is missing a pectoral muscle or something and it causes his shoulder to slump on one side lol