My son's age is 7 year. We seen his chest bone (sternum) is seen out side from chest since 1 month. He has no problem. His daily routine activities is normal. When we consult to a pedestrian he suggests us to his chest xray and vitamin d3 test .both reports are normal and Dr. Said it is normal. He gave us calcium tablet shelcal tablet and vitamin d sachets. Pls suggest what causes and what treatment is taken.