Hi Doctor , my child is 18 months and my son has a lump on his chest near his collar bone . At first it was 2 balls and now its one big lump. He had test ran an xrays, every thing was normal. Now he has a lump, can you help me. Hi Doctor, my child is 18 months and my son has a lump on his chest near his collar bone. At first it was 2 balls and now its one big lump. He had test ran an xrays, every thing was normal. Now he has a lump, can you help me.