All Of A Sudden I Have Random Pimples/almost Boils Popping

All of a sudden I have random pimples/almost boils popping up. They started when I was seventeen on my butt. Then they started getting less and less over the next five or so years. I would get them under my arms about a foot down from my arm pit. Then last spring a had diverticulitis that resulted in an abscess diverticula. I had a sigmoid colectomy and a LOT of antibiotics. They went away for almost a year. They are coming back all of a sudden within the last two weeks, kinda all over my body. What is this?