When I went on the raw foods diet, I went thru several detox periods, and one was my lymph glands in my armpits because swollen, red and hurt like hell. It scared me, but I also thought it was kind of cool because you could see the detox happening. After a month or so, they went away, and I've not had any soreness there at all.
Check to see if in each armpit you can feel a small round hard bump, or look in the mirror and look for round red swollen bump in each armpit.
If you feel it's swollen lymph glands, then it's detox.