I do half an hour of yoga postures almost every morning. When I don't do them for a few days I get pretty bad back pain and migraines. when I am doing them, no problems at all.
Before doing that doctors would give me injections and muscle relaxers all the time. I am pretty sure I either would already had had surgery or would get it at some point if I had followed doctors' advice.
The trick is that you have to adjust your exercise routine to your specific problem and adapt constantly. This is not easy.
For me it's the sacro illiac joint. It tends to get misaligned and then I get headaches. A yoga teacher gave me a series of exercises that bring it back into alignment and also strengthen the surrounding muscles.
This is very individual and probably won't work for other people.
In general look at the DVDs by Gary Kraftsov. His stuff is very simple but very effective.
Many will do McKenzie Method work ($10-15 book on Amazon, Treat Your Own Back) for lumbar pain in flexion. It is very specifically good for that and that alone, which is the most common form of low back pain. I found a lot of relief using the tools in the book (yoga-type postures) and weight lifting.
Before doing that doctors would give me injections and muscle relaxers all the time. I am pretty sure I either would already had had surgery or would get it at some point if I had followed doctors' advice.
The trick is that you have to adjust your exercise routine to your specific problem and adapt constantly. This is not easy.