I have many small lumps on the side of my armpit up to above my breast. They are sore and feel small and round but are only on one side.?

Lymph Nodes. Hello, This sounds like you have some lymph node that are swollen or inflamed. If this is the case, it can be the sign of an infection or other process going on. This should be evaluated by your physician. If the lumps are in the breast tissue and not actually in the armpit, they could be cysts or a different mass of the breast. In any case, get seen and make sure all is well.