Hi,
I know what it feels like. I've had bacne forever.
The thing that has really worked for me is tea tree oil soap. Dr. Bronner's has a good one, but there are other brands. I put it on a bath sponge in the shower. It's nonirritating and leaves a nice clean feeling. It's done a lot to clear up the pimples on my back. I'm also on Retin A Micro, which has worked pretty well on my face but never cleared my back. I'm 95% clear on my back now.
Good luck.