Acne suddenly on back & chest?? Help please.

As if my face wasn't enough to deal with, I'm now getting acne all over my back & chest more than ever. I've always had a few pimples here and there on my back, hardly ever my chest, but since about a month ago I've had on going breakouts left right & center. And not to mention, I've noticed a couple pop up on my stomach!!! Along with some itchiness along the lower abdomen. I've never had a pimple on my stomach (by the way I noticed this after I tried doing castor oil packs for 2 weeks). It can't be diet, because I've been eating practically the same stuff for a while which has never affected my back, and my diet it pretty good if not fantastic. If it's hormonal, why now? Why all of a sudden? My face has it's really bad times, then gets better, then gets bad and so on for like the last 9 or 10 years. I feel disgusting because I can't wear tank tops and such during summer, and now I can't even show my belly due to the bumps or redness caused by itching. What the hell is going on? Any ideas? By the way I'm female. Thanks.