Low back pain has various causes...also it is one of the most common complain.... since you have described your problem in brief i need to know certain facts...
1)have you taken Xray/MRI of your lumbar spine? 2)what was the diagnosis when you first started getting back pain? 3)What treatment/medications were you on that time?4) What is your height,weight and occoupation?
5)have you done your calcium/uric acid levels test in the past 6 months?
6)is your pain continious or comes and goes...also do you get morning stiffness and pain or get in on some activity?
Do let me know the answers to the above question and ill help you with proper diagnosis and treatment