[Cloud9Fitness]

A horizontal clavicle that articulate at the same level of the sternum as the other clavicle, and in the absence of trauma and remodeling, likely represents a depressed shoulder/scapula of the horizontal side or a downwardly rotated scapula. Essentially, the AC joint is lower on the horizontal side.

If you are right handed, then this would go along with relatively dominant/short pecs and lats and weaker scapula control (relatively weak traps, serratus anterior, and rhomboids).

If a trainer tests you for these things, and they are positive, then a variety of closed chain exercises (i.e. push-ups, push-up pluses, swiss ball arm circles on a wall), kinetic chain exercises (i.e. PNF pattern arm raises), and stretches (for the pec and lats) may be helpful over time. These may also reduce the risk of pain in the future.