Hi, I have a weird mass under my arm (armpit). I don't believe it is a tumor. it has been there off and on for like 2 years but always very small. It never really did much and I always just assumed it was an ingrowm hair. I am 8 months pregnant now though and throughout the pregnancy it has grown a fair bit.. sometimes it hurts and sometimes not. It's fairly big now (about the size of a grape) but changes a bit in shape and size mostly it stays round, but sometimes gets more oblong. I'm really confused because it doesn't really fit the description of anything I have read. I am just curious if any of you know about cysts and their characteristics. I have a feeling that might be what it is. thank you.