E.W.
I had multiple pea sized lumps and they were semi-painful to touch - I was FREAKING OUT!! I went to my MD who said it was swollen lymphnodes - I had recently hit my head and received a sizaeable bump on my fourhead as a result, when the fluid drained from the bump on the fourhead it was filtered through a series of lymphnodes (apparently it didn't bother the ones in my neck), but when it got to the ones in my armpits it caused them to swell. They gave me antibiotics and the lumps went away in about a week. The only thing for me was, because they were painful, I couldn't shave until they were gone (because it hurt & because there were so many that I would cut my skin really bad as well). Even though this is something minor (most likely), you should still see an MD so they can treat it appropriately.