I have been having similar under arm pain in my left armpit for over a year.
I thought it was my heart, but I have done some tests and my heart seems fine.
But this very annoying on going 24/7 pain is really a total "pain" in the butt.
My doctors will not do anything for me.
I also have a skin tag in the same underarm, that could be an option. I wish my doctor
would give me some caring and more then 5 min...
Tired of the naggin pain...