I developed Fibro a couple years after CRPS. There were some differences, IMO, but the pain was certainly not anywhere near the level of the CRPS. For me it was that the joints would hurt all over my body, while my CRPS is limited to my right foot and leg. And I would feel physically like I had been knocked down with the flu, without actually being sick. And each time it happened I would get a weird mild rash on my cheeks and neck. Etc.

I have also heard that CRPS and Fibro may be related. But heck, there is so much that they don't know about both conditions, other than they are both nerve conditions.