‘Spondylo’ is a term used to describe the vertebral bones in the spine. ‘Spondylosis’ refers to stiffness or changes in the motion at the joints of the spine.
Anything that changes the motion at each spinal segment can cause spondylosis. For example a narrowed disc space compresses or pushes the joint surfaces together. Joint motion can be limited and painful in such cases.
Bone spurs or other arthritic changes around the edges of the vertebral (facet) joints can also cause spondylosis.
Discogenic disease refers to changes in the discs that cause pain. This could be disc protrusion or herniation. In such cases, nothing shows up on X-rays. MRIs or discography is usually needed to pinpoint the disc as the cause.
It sounds like your discs are fine but there may be a problem at one or more of the vertebral joints. Be sure and ask your doctor to go over the X-rays and results with you for a better understanding of your own spine.