Hello Jobe :-) I my case, one of my lower back vertebra has a genetic defect. One of the little " wings " that stick off of the vertebra, which the muscles that support the back attach to, is missing, creating some instability when I pick up things or bend over, which makes the affected vertebra slip sideways, impinging on the nerve within. It happens every once in a while when I forget, and am not as careful as I should be. Feels like its starting to heal up so I'm hopeful to be hiking again soon. Maybe to DCHS sometime this next week :-)