Advice: Working out a lot- Can't stop STRETCHING

So, recently (as in the last month), I have taken up boxing. It's awesome, I punch things, and I can tell I'm getting better.

However, when I have down time, like when I'm at work, my whole upper body has this itchy/annoying feeling like I need to stretch, but I just can't seem to stretch enough to get rid of it.

Has anyone else experienced this? Any advice on how to make it go away? I've worked out before this and I've been an athlete in my younger days, so I'm familiar with muscle soreness and things like that... This is a new beast to me. Just thought I would ask