I work on my shoulders a lot with iso machines and free weight shrugs. One thing I noticed on other guys is that their left and right collar bone are evenly parrellel, meaning they make a straight line below their neck. When I am standing straight, mine kind of tilt inward in a V shape. I noticed that if I try to lower my arms, they become straight and my shoulders look a lot better but I am straining them. Is there some exercise or stretch that helps lower my shoulders? Thanks for any help.