Have your doctors every prescribed physical therapy or water aerobics? Both of these would be good for you.
Yes, prednisone will thin your bones. I'm dealing with that now. My back also hurts badly at night. It's like someone beat me with a baseball bat but I now have a pillow top mattress with a foam egg crate on top of that and a fiber bed on top of that! This helps keep the bed softer but yet firm for my bad back.
Below are a few things that have helped me with lower back problems. I don't have that very much anymore. My back pain is in the middle of my back, my shoulder blades and along my sides. These things might help you, too.
First of all, I do not sleep flat on my back because it makes my back hurt more. I don't sleep on my stomach either. I sleep on my sides with a pillow wedged behind my back. This way, I can partially be on my back but have support. That helps me. I also get out of bed using a cane. I roll on my side, draw my legs up in a sitting position so the legs are actually hanging over the floor, and then I push off with the cane. Gravity will bring your legs down and you will be pulled to a sitting position without using your back muscles.
When getting in and out of a car, sit on the seat with your feet on the pavement. Then, either using the seat or the steering wheel, swivel your feet into the car while keeping your back straight. I buy cars with leather seats because they are slippery. But, when I rent a car and get cloth seats I had to come up with another idea...and I did! I get a garbage bag and a towel. I lay the garbage bag on the seat and the towel over it. Then I do the above. The garbage bag and towel let your rear end swivel like you were on a lazy susan! LOL Just reverse the above to get out of the car.
Don't use your back muscles when you are lifting things up. Use your legs instead. By doing the above things, my back rarely hurts me now. I hope these suggestions will help you, too!