My wife has been noticing these slight dark circles on my chest and the back of my neck. And she says they have been growing slowly over the last year. I'm 25, male, rarely in the sun for long periods and overweight. (245lb). The circles don't feel rough, dried out, they don't itch and if no one told me, I wouldn't have noticed.

Here is a picture of the spots: http://imgur.com/a/IhcOH

What is this?

I looked it up online because I have those on my upper chest also. They said it's a skin condition and harmless. It can be due to acne or the sun.