When my 31 year old son holds his shoulders back, he is noticing a round protrusion that seems hard, but it is round. He is 6'6'' tall and weighs 230 lbs. He says he noticed it a couple months ago, and when his pets jump on his chest, it is sore. I felt of it, and it feels round and hard, but you can see the round shape. He has lost a little weight. Could this be something he has always had, but is just noticing it?? Please advise. Thank you.