Another avenue to consider is possible injury to the long thoracic nerve. This nerve innervates the serratus anterior muscle which protracts the scapula, assists upward rotation, and stabilizes scapula against thorax. Some asymmetry in scapular position is certainly observable in pictures. This could also account for difficulty during bench press as the serratus works hard to protract scapula. This nerve can be injured via direct blow, compression against chest wall (backpack injury), or repetitive strain. Any thoughts on this?