HI BO728… Thanks for responding… I used the words “lock up” cuz i didnt know how to describe it. But im thinking its either and nerve thing or im subluxing or dislocating someting in my back. It only happens when i streach out my back,like laying on my stomach or twisting my body to fast or far. And there is nothing i can do to make it better:( just have to ride it out. Usually getting out of the position helps a little but not much… Im guessing its due to my EDS but im not sure. Just got diagnosed.