Wow....yes, i've had that happen since way before i even had surgery. My spasms spread all over the place. My posture was terrible because I was literally bent over almost 90 degrees forward, and I used to think that was the full cause of all my upper body spasms. However, I have gotten upper body spasms & cramps after surgery, even at times when I was feeling okay in my lurabar spine. Sometimes I get it terribly in my neck and into my left shoulder. But even right now with the pain i'm having, I do bend over slightly again and to the right. (probably b/c my left lower hurts more). But yes, while my low back is spasming, it does creep up almost my entire back up to my neck area. And you can feel it, because my whold back becomes rock hard. And I usually am soft due to the fat i've gained. Sometimes I plaster those stick on heat patches up my whole spine & it helps a little. But the big moist heating paRAB help more. But when I take Soma (350mg 2x / day), the spasms calm down alot. They are still there but do not hurt so much. The bad thing is, that i've not taken any Soma in the mornings otherwise I am a little dizzy, drowsy, and cant concentrate well enough in school.
I know what you mean about not knowing whether it's from teh stenosis or posture related. I am not too sure myself, but I am suspecting I have problems going on in my neck area as well. Sometimes while laying in bed, my hanRAB get pins & needles and my arms aren't even compressed. I also get on & off pain in a certain area of my cervical spine, which then always turns into a headache, which goes up the back of my head, spreaRAB to the sides and around to the front. it even makes my jaw joints hurt. I notice this happens sometimes when weather fronts come in.
I've never had my neck MRI'd or anything, though (my lurabar was always worse so I concentrated on that). Have you ever had your upper spine checked out?
Also, do you seem to get any pain that seems to be in the cervical spine area? Or spreading out to your shoulders?
When this happens to me, my whole head feels like it's too heavy for my body and I wish I could just take it off....