I really can’t believe the blatant ameratzus going on here. Please do NOT make up halachos if you never learned the sugya at all and never even looked up the Shulchan Aruch.
The sugya is in mainly based in Nazir 58b-59a.
It is %100 muttar, l’chol hade’os, to shave chest hair using anything but a razor, and that is the STRINGENT position of the Shulchan Aruch. Many rishonim hold even with a razor, but for all practical purposes, the SA in YD 182:2 says it is muttar without a razor, i.e. the same as shaving the face.
Regarding armpits, the SA follows the stringent opinion in the rishonim that any kind of shaving is assur, but qualifies that this is only ????? ???? ??????? ???? ??? ????. The Rema says that in a place that men also do it, it is muttar l’chatchila. R’ Akiva Eiger on the spot says that with regard to this we look at the goyim to see what is normal and follow that. Please do not dismiss what I am saying without seeing it inside. I am not sure if in America it is possible to say ??? ??????? ???? ??? ????. Therefore I do not think even the issur on armpit hair is so clear-cut.
The ikkar is you should ask a rov, but please everyone, stop making snap judgments about halachos you apparently have no clue about.