Was itching in my friend's bed, woke up with itchy red bumps underneath my breasy area, it looks like a disease. I want to know what kind of bug bit me?

Was in in hotel ? If you woke up with rash under breast area ( generally soft spot) check o also hands , behind knees, groin, arms.. For possible "scabies". It is transferred by close contact - saring, bed etc. For definitive answer see your primary doc. And am other members of home if any rash too?