HI welcome to healthcare magic...........
Its pretty tough to tell what those lumps are , without examining their characters.
Its also a very unusual site too.
The most common possibility would have been a heamotoma secondary to collar bone fracture
, but X-ray being normal rules out that.
The only advice i can suggest is to get a FNAC i.e fine needle aspiration cytology of the lump. U can go to a pathology lab and ask them for a FNAC of the lump. Wat they do is , put a needle in the lump and take a small material and study on microscope and then tell you what it is.
Hope i was helpful...