Bro, sorry if I missed it but were abouts is your back pain, upper, middle, lower or all over ? As the others have mentioned strengthing back muscles is definately a key step. Look at yoga and pilaties, check your local church, community halls, etc. There are quite often classes for a few quid. And there are LOTS of web sites with exercise suggestions, just good it.
Two other items I would also mention,
- Posture. Tied in with muscle strengthing if sit for long periods at work for example then consider how you sit. Have a look at your chair, its position, how high your desk is, etc. Again google is and have a work with your boss/hr department. If you work for somewhere big, you should be able to get an assesment done else you will have to do it yourself. Again Google is your friend here.
- Weight. Tied into the above two, I dropped a some weigt over last 12 months and notice a difference in my back pain. Of course I worked my back muscles in losing in losing the weight but I am sure both had an effect.