why does 'no peito' translate to 'my chest'?
Plus, in Portuguese we usually don't use possessive with parts of the body if it is plain in the context.
Both "in my chest and "on the chest" are accepted, guess they assume you cant feel someone else's chest.
Breast is correct too. http://www.linguee.com.br/portugues-ingles/search?source=auto&query=breast
Breast pertains to the fleshy part outside the ribcage, whereas we use chest to mean the entire area including the chest cavity inside the ribcage. Someone feeling internal pressure would use the word chest.