It was really hot today. and i was wearing a pushup bra. and when i took it off at night my boobs were hurting really bad like they were burnt. why?

Sunburn: If you were exposed to sun, you could have sustained sunburn. Mild redness and burning in the skin would confirm that. That would resolve in few days.

It's the effect of: Heat, pressure and compression on your breasts. Go see your dr if your symptoms get worse esp if u develop fever or pus. In the meantime, u may take tylenol (acetaminophen) or nsaids for pain and apply ice packs for 2 days then warm compress. Hope u feel better!