I do not have any expert advice.
However, I do have my own method of dealing with this problem. It simply involves standing up and walking around. Sometimes, when I need to read something, I do it standing and while walking around in the office instead of when sitting down. I will also get up regularly. Sometimes to get a glass of water. Other times just to stretch.
Another thing I do is keep a correct posture (most of the time, not even close to all the time, though I should), and make sure that everything is set up correctly (Desk at the correct height and so on). All of this goes a long way to prevent problems and keep you comfortable. I have had lower back problems that are caused by a sports-accident. I did all of this to prevent this becoming an issue in my every day working routine, and so far, it has really helped.
What you do outside the office / workplace is also important. Getting enough exercise and doing sports makes you a lot stronger and more flexible, and enables your body to deal with a lot more abuse.