How Can A Collarbone Edema Which Is Painful Be Treated?

Hi my dad has a raised area on top of his right collarbone it is more like edema not really formed like a knot. He says it isn't very painful but says that shoulder hurts and has done that for years bit the edema has just been there about a month. He says it feels like it is spreading toward the midline of his neck what could it be?