Is it a problem if I place my radio on my chest?

As long as you’re not floating in a bath tub or swimming pool, you’re cool. lol

No problem at all. Unless the radio is a transmitter. The radio waves are passing through and around you whether the radio is on your chest or not. Your body is basically a, elongated sack of conductive salt water – an intricate antenna tuned for many wavelengths.

Considering the volume of different types of waves that penetrate our skin on a daily basis… a radio has no chance at causing further harm.

.

This one, maybe.

It won’t cause any harm but it might be more convenient to get an aerial for your radio.