I've had this problem too; my chest, back and shoulders being particularly bad. My doctor prescribed antibiotics which cleared the worst of it up, but it came back within a couple of months. Since then I've been on BC pills that have worked wonders. My skin is totally clear, though you said that isn't an option for you. I can't be much help otherwise because no creams or lotions or scrubbing ever helped me at all.
It's been a few years now and I'm so nervous that the acne will come back as and when I come off the pill.