Yoga can be a perfect addition to your fitness program, especially if you have low back pain. Yoga helps improve your flexibility, core strength and balance.
Studies also back it and I'm also living proof that certain types of yoga (more mellow such as flow) really reduce low back pain and it also helps with the relaxation component of your wellness program.
As always, consult with your physician before starting any exercise program. It's also a good idea to meet with a knowledgeable certified yoga instructor before you dive into just any class. Go here to find one in your area: http://www.yogafinder.com