I feel ya! Have you tried physical therapy? I was going twice a week and my back pain (lower) was gone, but then I stopped going (I couldn't find anyone to go with me to keep Jude entertained) and it came back. A few things they had me do were...
Sit in a chair and bend my leg from the knee down under the chair with a resistance band looped around my ankle (3 minutes on both sides)
Bird-dogs (I think that's what they called it), where you get on your knees and extend your left arm and right leg straight out, and alternate opposite limbs like that, for about 5 minutes. They put a long wooden pole on my lower backand I had to be careful not to let it wobble or fall off.
Balance on half an exercise ball (the flat side was thick plastic, about 2" across)--balance with the ball side down and bend my knees to where I was in a sitting position, then come back up, for about 3 minutes. Then I flipped it over so I was standing on the rubber ball side and alternated standing on one foot for 30 seconds each foot, for a total of 5 minutes.
Tie a resistence band around your knees, and with your knees bent while lying on your back, keep one leg still and extend the other leg outwards (sideways), 3 minutes on each side.
15 minutes on the exercise bike.
Obviously I'm not a doctor and I'm not trying to give out medical advice, but those are just a few examples of things they had me doing that helped. If you can, I'd recommend doing physical therapy (if you can't go every week or very often they might just give you directions for a few exercises to do athome). Good luck! Back pain SUCKS!