My disc herniated and the part that squished out pushed up against the nerve in my leg. The pain was extreme. Basically your disc is kind of like a jelly donut. Harder on the outside, softer in the middle. If it get smushed the inside will protrude out and push against whatever, in my case it was my nerve. It will never heal on its own, all they can do is trim off the piece that pushes out and hope it does not squish out anymore.