Did you injure yourself somehow? Had you been doing heavy lifting or anything that could have caused it? I'm guessing you have a muscle issue. Have you tried stretching? There are several yoga poses that do a great job of stretching the back, like the prayer pose, or cat and camel. Going to a physical therapist may help, especially if you have cramped up muscles. They can manually get the muscle to relax or they can use this electronic stimulator (not painful, just makes the muscles contract and relax). In the mean time, a heating pad or a soak in Epsom salt along with some over-the-counter non-steroidal anti-inflammatories probably will help.
It could also be an underlying condition, like gallbladder problems or something. In that case, you probably should see a doctor. And why are you so against going to the doctor? Wouldn't that get you "real answers"?