Pinched nerve, 20 weeks.

I am currently 20 weeks pregnant with baby #2 and I believe I have a pinched nerve in my upper back. It’s like right behind my shoulder blade at the very bottom and it hurts really bad when I breathe in. I’ve had pinched nerves before, but never when pregnant. I had some sciatica with my first son, but this is not that as it’s not a shooting pain down my back and leg. Is this something I need to contact my OB for, is there any ways to help relieve pain? I know pinched nerves kind of have to run its course but it’s making it really hard to breathe and to take care of my 14 month old. Any advice is appreciate, TIA!