Yeah, I completely understand that. My first back injury was when I was 20 and leaned over the fender of my '70 duster trying to line the tranny and the engine up during a motor swap when the tranny fell off the blocks and yanked me over to the ground, ripping my lower back. About 5 years later, an big overhead garage door collapsed off the tracks while I was lifting it up at my shop and it landed on my head/neck wrecking my upper back.
About 15 years ago I developed an arthritic disc between the uppper and lower back than has fused making each end of my spine work independently and become terribly pinched from the lack of mobility between the two. I can only stand or sit about 20 minutes at a time before I need to get everything moving again and avoid severe pain. Air travel or long drives are brutal.
It ain't the age...it's the miles.