Lumps on or around the collarbone can be caused by many things. More often than not, it's something minor and temporary. If, however, a lump lasts longer than a few weeks, grows, is painful or has no distinct borders, medical attention is required.
Swollen Lymph Node
A network of nodes throughout the body comprises the lymphatic system, part of the immune system. When exposed to viruses or bacteria, these nodes will occasionally swell. Frequent sites of swollen lymph nodes due to infection are in the neck and chest, along the collarbone.
In addition to simple infection, a type of white-blood-cell cancer, called lymphoma, can also cause the nodes near the collarbone to swell. Other types of cancer, such as breast or bone cancer, can result in lumps on or near the collarbone.
A lipoma is a fatty lump, usually located between skin and muscle, that moves slightly under finger pressure. Lipomas can grown anywhere on the body, including the collarbone area. They are harmless and rarely require treatment.
If the collarbone lump appears suddenly and is accompanied by severe pain after a fall or impact of some kind, it might be the result of a broken collarbone. Treatment typically includes placing the arm in a sling for up to a week for adults and three to four weeks for children.