What could pain in my back from taking a deep breath mean?

I have been experiencing back pain (localized to the middle-to-upper right region of my back) all day, especially when I take a deep breath. I've also noticed I get the pain when I move my right arm in certain directions, as well as if I twist my back to the right or left. But the pain is the worst when I take a deep breath. Could this just be a muscle strain? I'm not sure if pain from a muscle strain can be felt from taking a deep breath. Any advice and/or information would be appreciated.

Thanks.