I don't have the chafing problem, but my god I feel the boob thing. I have trouble going on roller coasters and stuff because I can't breathe if my boobs are smashed against my chest.
I wear like shape wear or spanx booty shorts under pants and dresses and shorts they help and make you look a little more slender I'm not fat by no means but I have thick legs you can get a cheap version at Walmart
https://www.amazon.com/Lanacane-Anti-Chafing-Gel/dp/B0015X8418
(In this case anyway)