19 yr female.painful, small, lump under the surface of the skin in armpit. has been recurring. lasts for a little over a week, comes every couple mont?

Possible staph: Many causes of painful inflammatory conditions of the intertriginous zones of the body (e.g. skin folds). One major cause is recurrent colonization with staph (bacteria) due in part to the local environment which is ideal for bacterial growth. If you are shaving your armpits, you may be introduction bacteria by using or re-using razors which cause trauma of the skin which can lead to "bumps".