You're using the "superhero" morph setting, aren't you, and it looks like heck on the chest and shoulder area. Instead, highlight the individual areas for the entire body and use the "hero" settings, but don't crank the dial any higher than 0.5. Then go through each body part and adjust the x, y, and z settings (like on the forearms, settings of 105/105/114 -- experiment and you'll see what works with each part), and you'll find the musculature a little more natural.