From age 22 to about 42 I had a lot of lower back pain and after an MRI (yes, it took me 20 years to finally have it really checked out) it was determined that I have a partially herniated disk.
I had read somewhere about core strengthening. For most of those 20 years I was working on a farm and surfing but man, my back would tweak and I would walk like a cripple for about a week.
I tried stretching and it would work, but only for temporary relief of the symptoms.....mainly pain.
So one day I started doing situps. And within 3 weeks I could feel a major difference. To this day, I'm almost 57 now, I still do abdominal exercises at least 2-3 times per week and I never get those tweaks anymore. My back is still a bit stiff if I've been sitting crooked for too long or something but I can lift things now and man, it's made a huge difference in my life.
I know there isn't a universal fix for all back problems but this worked wonders for me.