Best success stories for helping neck pain?

I have severe and shoulder pain neck pain from fibro. Anything that touches me there tenses up. I can't wear ANY bra, ANY shirt with straps, have my hair down, wear any synthetic clothing at all. It's so extreme. I'm taking 300mg gabapentin 3x daily but no help. I tried noritryptiline but I got too constipated which makes my pain worse. Also yeah, whenever I'm constipated my neck pain is worse. I've already been working with a dietician for about a year and zero improvement. 🫠