after making sure it's not a fracture, bone spur, or crack at the drs....
-ice during workout and after
-heat with those hot water bottles you fill up with hot water (you can get them at stores like Walgreens, Longs)
-Vicks, or Bengay, or Icy Hot - I like to use Vicks, but poeple in my gym use the other two, and also the Bengay/Icy Hot patches
-massage and stretch it out. stretching splits when lying down on your back actually can really help a lot for lower back pain because it stretches that part too! it's a yoga stretch too. :D
-hang on a bar, kind of 'jump' on the bar while hanging on it, maybe twist side to side while hanging on the bar - test to see what works for you and feels good
the stretching is really good for preventing lower back pain. also be careful of your landings, don't land on your heels. strengthening your back muscles and abs is good too!