You can give "rhodiola rosea" a try.

Not sure if it helps in your case or against back pain in general but it helped my runners knee a lot a lot.
I normally have a lot of pain in both my knees after about 12km of running.
When I took it this stopped and I could run for 20km and longer.
Not sure how it works.
Additionally I experienced some weird sequences of starting to cry during running and during normal walks in nature.
Kinda weird but it stopped after a while.

One of the few supplements which actually had an effect on me and I tried a lot.

I made a tea first and later just chewed the root pieces and swallowed them since it was easier, faster and nothing was wasted.
Still taking it at least once a week.