I have found there is a pretty substantial link with the two, it is said over 50% of Fibo suffers have SFN...

Fibromyalgia: It's a Nerve Disorder - Power Health Talk

Yes, SFN, fibromyalgia, (and BFS) all appear to be very closely related.

But, I haven't figured out if they are different presentations of the same disease - or different diseases that just happen have small fiber nerve damage as a common symptom.

some fibro doesn't have nerve damage. They call it central sensitization - more of a central thing vs peripheral I guess. It's interesting to see what they are coming up with for the diagnosis of "muscle pain". I hate that diagnosis anyway.
fibro-muscle, myalgia- pain. It really irks me. Even before the sfn was diagnosed the doctors apologized for giving me such a waste basket diagnosis. NO duh, my muscles hurt. Now tell me why, now they find the nerve damage.... okay, there's why, but how come that happened. SO frustrated and this NY weather is making me hurt and !

I attended a live all day seminar on chronic pain a few years ago that had a portion on Fibro.

At this presentation Dr.Clauw, at the University of Mich, was featured.

At that time he shared research that Fibro was most likely a CNS disorder where pain signals are inflated by the brain and spinal cord.

He gave stats of trauma (car accidents, war) and other pain states that trigger Fibro in people who have a family history of it. (Rheumatoid arthritis, neuropathy, RSD, were some of the conditions that can trigger fibro). He found in his research that fibro occurs in families, but at various historical times this was diagnosed with other names.

Dr. Clauw is a very good resource to listen to and read:
Chronic Pain - Is it All in Their Head? - Daniel J. Clauw M.D. - YouTube

He is on the net at various sites giving interviews that include fibromyagia information. I think you might find him helpful.

so the people with measurable nerve damage were probably misdiagnosed in the first place I'm thinking. The muscles and fascia are innervated hence the terrible muscle pain of body wide neuropathy. I suppose that in history it was classified under rheumatism as most of us here would have been categorized. God.... they would have been making us down bottles of opium and bloodletting back then.

Just as an aside...I am experimenting wth 2 types of
Body sleeves. One is for my arm and the other for my
Knees. While on my pain is much less. When off the
Pain returns.

The knee sleeve is by Mava and I found them at Amazon.
It seems that this gentle compression changes the
sensations enough to reduce pain in some way.