I have very light sensitive skin since i was a kid. I stopped using soap.
I also had rashes under my breasts living in a tropical climate.
Last year when I spent a very long time in the hospital they gave me "Secura personal cleanser". It's wonderful! My skin is completely clear with no more rash anywhere.
I use very very soft non scented disposable cloths - spray the Secura on it and rub gently all over my body. I smell so clean.
It starts with a cinammon sort of scent but dissapears very quickly after putting on. You can keep a spray bottle in your purse for personal hygiene too if necessary. On weekend trips with my BF I just take it in a 4 ounce spray bottle. It is really worth a try. You can get 3 or 6 bottles of it on Amazon and not expensive.
I used to use Dove sensitive but that didn't work much either. Stull rashy. Rubbing makes things worse. I never took long hot showers either.
PS. Has anyone here heasrd of a skin condition called "Grover's disease"? It starts under the breast and goes down to about waist in front. Very itchy. There is no cure for it. It's strange!