I'm 57 and have chronic arthritis in my lower back from old tennis injuries, and have had some really bad bouts were I could barely walk. The one thing I do every day, which has made a huge difference, is stretching my back in the shower when it's warmed by the water. All it is is touching my toes with straight legs half a dozen times, and then stretching my calves. It really stretches your hamstrings too. I've been doing it for about 6 years and haven't had a single acute episode since. I also have a full yoga-like regimen that I do whenever my back is sore, usually after lifting stuff.