My son is 13 years old and I notice a hard, bone like lump right post clavicle , I took him to the doctor and they sent me to Childrens. There they did an ultra sound and xray and both came back normal. The lump is hard and immovable, they called the general surgeon and he said to bring him in first thing monday morning. The dr did not say what it was but to take him to the surgeon. What can it be..I am worried either way..but at least if I know what the possible reasons are I can not feel so in the dark.