Well if you do not want to take any type of pills, I would suggest trying a prescription cream, or gel. These types of topically applied formulations, work much quicker then do pills, because they in turn bypass the stomach as well as your liver. In this way there will be no harsh side-effects to deal with. If you want to try some natural means altogether,then i suggest a combination of ice and heat packs.
However I believe the ice will work the best for lower back pain for example. Also pick up a tube of Aspercreme, or Icy hot patches, at a local pharmacy. Besides these different therapies, you can also try lying flat on a hard surface and doing some light stretching exercises, to make the muscles and tendons, a bit more pliable. Hope this bit of info. helps you on your quest to relieve your back pain.