I have had issues with my back for years ( I'm 67 now) and I still get a sciatic twinge down into my leg. However there are two things that seem to help. Firstly I take glucosamine every day which really seem to work. Our doctor recommended it too, so it seems to be getting some official recognition. The second thing is gentle exercise.
Most mornings I lie on my back, knees drawn up, and move knees to touch the ground on each side, repeating about 12 times. Then, lying with straight legs, raise one leg slowly and stretch to opposite side as high as possible, toes stretched. (Right leg to left shoulder and vice versa). Repeat with other leg. Again repeat - I do about 12 of these with each leg.
Finally, lying with knees drawn up, raise the back as high as possible and let return to the floor. Again repeat.
When my back started playing up I started with about 5 repeats and have built up to 12 repeats, and that seems to keep me reasonably flexible.
Seems to work for me.
K