Hi Samantha,
I am newbie and haven't had a chance to introduce myself yet but wanted to reply to your post. Ouch! Ouch! Ouch! Your symptoms sound very much like mine!! I also started getting boils when I was about 20 years old in the very same places you mentioned. I have gotten them under my arms, in my groin, under my breasts, on my bum and around my stomach. 15+ years later and I have finally been diagnosed with Hidradenitis Suppurativa. Not sure if this is what you are experiencing or not but wanted to pass along the info in case it could help.
Take care and hope to see you around the boards!