Slip Disc:

A slipped disk occurs when the soft inner portion of the disk protrudes through the outer ring.
Symptoms vary based on where the slipped disk occurs and if it compresses any of your spinal nerves.
Slipped disks are more common in older adults.

Knee Pain 

How to deal with slipped disc and severe back pain

Aslipped (prolapsed) disc often A causes severe lower back pain. Although patients often talk about having a slipped disc, nothing in your spine has actually slipped out of place. Having a slipped disc means that one of the discs, which sits between each of the bones in your spine, has been damaged. When the disc is damaged, the soft gel-like inner pad of the disc squeezes out through a weak point in the outer layer, causing a bulge that often presses on nearby spinal nerves.