I know you know this but, protect your backs at all costs. Mine is fooked.
I have a degenerative back condition, and have had to change all my fitness to find things that don't cause pain, or set it off. I have discomfort daily, but there are plenty of things I can and have done exercise wise to keep fit, and have just worked round it as best I can. No free weights, only machines as they offer more support, and sadly had to give up running and change to cross trainers, with the occasional jog. Not what I wanted to do, but its what I needed to do, and am left with less injuries and better fitness.
If you want any advice on pain killers I have been on Codeine for years, as well as the anti inflammatory Naproxen, as well as omeprazole which counters the effect Naproxen has on your stomach (apologies if this is teaching you to suck eggs)
Hope your backs are better soon!