I have herniated and degenerating discs L4/5 and L5/S1 which cause sciatica, at its worst, all the way down to my foot.

Stretching and Pilates helped me. Chiro helped initial acute pain, but then became kind of useless.

Doing a lot of crunches, and only working one group of muscles made it worse. If you're going to do crunches, do other core exercises to keep a balance.

Swimming makes my back hurt - if I try doing a lot of freestyle laps. Back extensions (arching back, instead of bending forward) makes things worse.

Running made it worse - too much impact.

Getting a bike that fit me properly helped a lot to ride pain free.