I have an infection under my armpit that is very swollen, lumpy and red all around it. along the hard swollen area is bruising. any ideas?

Hidradenitis?: Likely skin abscess, perhaps complicated by spread of infection into an axillary (armpit) lymph node. If a chronic, ongoing problem, maybe hidradenitis suppurativa, an inflammatory problem not directly due to infection, although infection can complicate HA. Other possibilities as well. You need to see a doctor right away for diagnosis and probable antibiotic prescription. Good luck!