Uncomfortably numb

Advice time: since I got home, I've developed some kind of numbness/pain in the right shoulder blade that radiates along my arm. You'd think it could pick one--numb or pain--but no, it's both, and it's really uncomfortable and making it hard to find a way to sit or sleep that's not too hard on my abdominal stitches or makes the shoulder worse. I can't twist, so I can't really get back there and poke at it, and I can barely reach behind me. I think it's like a pinched nerve or a pinched…well, can muscles get pinched? I don't know, whatever it is is definitely becoming problematic.

Can anyone think of a way I could try to work this out, or is it something I'll need actual help for? I thought about trying to find a way to put a yoga ball behind my shoulder blade and roll it around but I can't figure a way to do that in my current state, which is basically big baby ball of pain.