Protruding clavicle at the sternal end... caused by injury or just being skinny?

My clavicles stick out where they connect to the sternum. It looks like 2 marbles under my skin. I am pretty skinny, 125 pounds, but I never had them when i was younger. I look at pictures in 4th grade, and they were not there at all. I broke my arm in 5th grade (I stuck my arms out when I was falling and broke my forearm in several places). After I broke my arm, it seems that's when they showed up. It is both sides of the clavicles, but my left is a little worse. Is it possible that I hurt or dislocated them slightly and that is why they are protruding? I don't think it is because I'm skinny, because the rest of my clavicles do not stick out. Should I see a doctor?