This has been driving me nuts for the last few years and it happens randomly without any warning signs. I get a pain in my shoulder blade that runs up the side of my face and also in my lower back, sometime it starts in the left side of my head. It feels like tenseness almost like constricting when you work out. This can occur for a few days to a week, then it will go away entirely. When this sets in, it also is accompanied by fatigue and I get irratable. I have been also experienceing anxiousness, like coming off of cigarettes a feeling of nervousness. Sometime the muscles spasm and when I sleep or relax, I get a twitch. Like I said it has been going on for years now but it is driving me insane because I know when it happens I will be often tired and irratable and usually I am very active and bright spirited. Please if anyone can help with this let me know.