Hi MadJock,
Wow, so sorry you've had this terrible spread from a kidney stent

This illness is incredibly unfair...
Welcome to the site, and I hope you find some hints and tips here that might help. We are a friendly bunch, and you are welcome to vent if and when you need to!
I have CRPS in my left side after spread from an arthroscopy on my left knee. It's all crazy really, I've been on different meds and tried various 'painkillers', none of which take the pain away. I'm doing ok at the moment on low dose Lyrica morning and night, and physio exercises and just general movement as much as possible. The pain is what gets you down, isn't it? Just not being able to get away from it, and not being able to rely on any med to really tackle it. I'm coping better than I used to though! I hope you find something that helps you, there are so many ideas on here, many worth a try

I'd give Epsom salts (unperfumed) a go if you haven't already, either in a warm bath or wrapped in a damp cloth and placed on your skin. I find it especially good during the hot burning phase.
My spread into my left arm is fairly recent, and it's quite a scary thing. I know I'd struggle if I had to go back into my wheelchair again - I've been out of it for the last almost 4 months with the better weather. How long ago did your spread happen?
Good luck with your treatments and I hope you find something that eases the burden of this for you.
Take care, have a better day, and keep posting!
Bram