lumps in armpit

i am 32 years old and am mother of 2 kids. during pregnancy of my 2nd child, i developed small lumps in my armpit. it pained  a lot and after 2-3 days, puss oozed out of the lump and it dissappeared. again after few weeks, another lump in the same armpit appeared, which also dissappeared after 2 days, after puss ozzed out. this has been continuing since 4-5 months. the lump is small tender and swollen. puss comes out after 2-3 days and it dissappears.
please tell me what it might be. should i consult a doctor, or is it ok.