I'm no scientist, but that is how I understand it too.
I read that "substance P" is a neurotransmitter that works as a pain messenger to the brain. There have been some studies done that show that people with fibromyalgia have much higher levels of substance P in their cerebrospinal fluid than do "healthy" people. I guess more substance P = more pain.
I think that an excess of substance P is one of the theories of how fibro is caused. (Now how that excess came to be or what to do about it - I have no idea!)
Austen