The worst (and first) time I hurt my lower back was by lifting my hind foot over the side of the tub after taking a shower'
For several years following that, It would suddenly attack me every few months without warning, to the point I'd turn around and look for the archer that just struck me on the left of center of my spinal cord with an arrow, or black out from the pain.
I was a big believer in avoiding Drs exercising the center/cause of the pain, and it took me a long time to find an exercise that isolated that pain. It turned out to be a small muscle/ligament group in front/Left of my L4/L5 That if I did forward crunches against resistance (~100#) while sitting upright seemed to heighten the pain...And over a little time (lifting to fatigue on a daily basis) really helped..I've been mostly pain free for the last decade, but I still remember having to use crutches to get in and out of the car or taking 20 minutes to get up or down the stairs while trying not to scream..
