@jrofri Well, I can tell you a little-- what little I know. I have seen a few web sites that included a map of "pain points" at different places around the body, including this spot. At these pain points, the FM responds to stimuli or to nothing, and produces a sharp pain. There are different spots for different folks. Why these points give the sense of pain I do not know, and nothing I have found yet says exactly why. But since FM (and PM) are both autoimmune, products of misfolded proteins, I suspect the fibrils getting into the nerves that relay these pain messages are the real culprits. When the fibrils invade the nerves, something bad always happens. It may be a pain, it may be death. And it seems that there are certain spots where the fibrils get into the nerves, such as the sensory-motor nerves between the brain and the heart, or the kidney, or the lungs, or whatever. https://bit.Ly/1w7j4j8