Hi doctor. A few weeks ago, I was thrown onto my back by a girl in basketball. I experienced pain and stiffness for a little while, but got over it. More recently though, I ve found my back cracking constantly. It didn t do it before that I can recall, and I m a little worried and curious as to what it might be. For example, when take a deep breath after remaining still for awhile, it will crack. And sometimes just simple movements cause it to crack. When I m stiff I find myself more and more tempted to crack it more thinking it will stop. What is it and should I be worried?