I'm not even sure how to describe it, except, I guess I have a large sternum and I really don't have any muscle down the middle of my chest. Even when I flex and squeeze my pecs together, one can still see sort of a "space", about an inch. If you tapped on that area you could literally tap on my chestbone. Are there any exercises to help build this up, or am shit-out-of luck? Any suggestions are appreciated.