A.P.
Wow-sorry you are going through this-it sounds terrible and so frustrating. This may be totally off the wall but have you looked into things that you might have stopped doing/using while you were pregnant. Strange that they cleared up then. My thoughts would lean to smoking, alcohol, exercise(because of the sweat gland thing), diet soda, etc. Who knows..maybe you are introdicing some kind of toxin in your body daily that you did not when you were preg. I will tell you that I used to get absesses in the groin area that sound really similiar to yours in my 20's. Since having kids I have not had them and I attribute it to a much cleaner lifestyle and most importantly to quitting smoking.
An alternative medicine doctor like the other girls mentioned could probably discuss this with you better than a regular MD. Worth a try I say.
Good luck.