hi my three year old son fell on to him right side a few weeks ago,, he was fine and could move arms, was abit sore but nothing to worry about. he was using arms without problems, a few days ago i found a large hard lump on his collar bone towards the throwt, on the side he fell, it feels like the bone its is not movable at all. had xray and doctor said it was fine no break and it not sure what lump is and just to observe it? im so worried he may have cancer he is in no pain can move arms and weight bear, completly fine in himself