Sorry to hear about your problem. The condition which you are describing is known as hidradenitis suppurativa
. It is a chronic infection of the hair glands and it usually involves the groin & underarms. First of all it is not a malignant condition and nor is it a STD
. Some people are just predisposed to developing this condition. You should consult a surgeon, who will do some tests to confirm this condition and put you on antibiotics whenever you have a flare up.
In some situations, the entire lesion can also be removed surgically.
Hope you get well soon.