I might get a chest tattoo one day, but not to cover the scars but just cause I like tattoos.

I think tribals could work fine, you could always do a partial covering (one side + shoulder for example) and then if someone askes you about your other scar, I think I once read that the scar looks like what you get when you've had a collapsed lung? And else tell people you don't want to talk about it.
But, yea, tribals. Better, Maori or Pacific tribals, though you would need to like the style ofcourse haha.