What Causes A Round And Pink Recurring Skin Rash On Body?

I have a skin rash that has been coming and going for a long time. It doesnt itch, its not rasied. It is blotchy and pink circles. I get it on my inner thighs, my stomach starting from the belly button and down (worst "outbreaks") my chest (on top and under my boobs also on the sides of them) also my underarms sometimes extended up my under bicep.