I have issues with my back too. Herniated L1/L2 dics, arthritis in L2, and muscles that are prone to spasms.
Physical therapy....yeah, right. It was useless for me, it really was. Swimming is the best therapy...and yoga is good too. Without knowing the mechanism or details of your injury it's hard to say what would be best for you to do.
There is a pillow that you can get to put between your knees that helps me a little when mine is acting up, and I've taken to wearing Kalso Earth Shoes exclusively, which helps no end.
Unfortuantely, sometimes the only relief for mine involves valium and vicodin. I don't like it, but that's just the way it is.