Susie is right. When I had my back surgeries, one of the aspects was decompression, to make room for the nerves that were being compressed.
Nerves take a very, very long time to heal.
I am 10 months out from my surgery, and I still have pain (a whole lot LESS mind you), but only recently did I start to get some remarkable and exciting changes in the nerve damaged areas.
It's a very long road.
Just because the surgery is over, the healing takes much longer to finish.
Hang in there. You'll do fine!