I don't know if someone else suffering with you will help but I am in the same boat. Mine is my left shoulder and it started out with severe pain!!! Less than 4 hours sleep with pain meds through the night. The doctor has me on celebrex right now and 2 months later....the pain in my shoulder is just about gone. I had Xrays that showed a slight narrowing of my discs but that may or may not be the problem. Could be bursitus, it is hard to figure out.
I don't know what caused mine to act up but I am being careful not to slouch, I have the mesh insert on my office chair back for the correct curve in my lower back. I also have my magnifying glass on my machine so I don't have to lean in to see where I'm sewing. Rotary cutting is a no no for a while yet because my left shoulder is the one I hold down the ruler with. It's frustrating and painful and takes time to heal. Hope you are feeling better soon.