I would consider visiting a chiropractor. I've got a very small annular tear in the disk between my L1 and S1 vertebrae, and it gives me some pain in my lower back from time to time. My chiropractor has helped me with it quite a bit.
Some chiropractors are better than others, but if you find a good one, they can really help you out.
Also, Rob Shaul of Military athlete and Mountain athlete has a lot of prehab/rehab type exercises on his website that he uses with his athletes. These are the two exercises he uses a lot for back strengthening (particularly lower back).
http://mtnathlete.com/subpage_detail...661&page_ID=14
http://mtnathlete.com/subpage_detail...395&page_ID=14
Also, a foam roller will be very helpful. I use a foam roller nearly every day, and it helps me tremendously.
http://www.roguefitness.com/the-grid-black.php
Some other things that I use frequently are hang - up boots. They are great for helping with compression in your back, and help to stretch it out quite a bit.
http://www.amazon.com/STL-Sl-Spyder-.../dp/B0055QDCHW
You could try an inversion table, but hang up boots will provide similar results, they cost less, and you can travel with them.
Also, icing it will help a lot.