small lumps

I am about 8 months pregnant and recently had found 2 slightly smaller than pea-sized lumps under my left arm pit. At first I thought maybe it had something to do with my milk coming in, but i seem to have gotten a few more of them. I noticed the other day that my razor had a few small rust marks on it, and wondered if maybe it is an infection due to that, however they are only on my left side when of course I shave both. The lumps are sore to touch, they are rather hard, and (if you hold your arm up over your head) they go up as high as the top of the arm pit. Are there any suggestions as to what this might be, or how to treat it? I see my Dr in 4 days, and thought I would ask for other people's input before then. Could it possibly have anything to do with my milk coming in, or is it some sort of clogged duct, or infection or something?

[Cleveland Clinic]

Dear missylaneus:  Multiple small hard lumps that are painful to touch could be many things, however, without examination, it is impossible for us to speculate on what this might be.  You should have your doctor examine them.