Healthy discs give you flexibility, allowing normal turning and bending. Each disc has a jelly like "ball bearing" core, that provides the cushion between discs.
Disc injury can be caused by trauma. Spinal misalignment can cause disc tissue to become a wedge shape, preventing normal movement.
Disc tissue can bulge, because of compression. This distortion can produce a lot of pain as it affects nearby nerves. Without treatment, this will ultimately result in disc damage.
If treatment starts before permanent damage occurs, disc tissue can return to a more normal size and shape, and normal function will be restored.