Pretty much what everyone else is saying - stretching and working out. I had back issues for a while in my early 30's and worked with a physiotherapist and developed a stretching and workout routine that has kept me pain free for years. Guys naturally have issues with having tight hamstrings and if you sit allot - desk, driving, etc, your hamstrings tighten up even more causing them to pull down on your lower back. If I don't keep up on my exercise and go all out some weekend by Monday I can hardly walk, so back to the stretching and it usually clears up in a day or two.