What causes pain and numbness feeling going down both legs?

Spinal stenosis: Or a midline disc herniation.

This can be related : To more common scenarios like spinal stenosis or a disc herniation or both but occasionally related to: a tumor, spinal infection, a spine fracture, a peripheral neuropathy or another radiculitis like a tertiary form of lyme disease. You should have an evaluation by your doctor to identify a cause and guide treatment.