Swaity, I had a couple major back surgeries too and learned to ride afterwards. It was probably the hardest physical challenge of my life but so worth it. I could barely even reach my feet sitting on my ass in the snow, had to hold my breath to get bound in even standing up. I found that doing squats helps with every part of snowboarding. To boil it down, keep at it no matter how hard it is. My back feels much better after snowboarding but I do need some Aleve during the day when I go because the muscles aren't used to that kind of work.
I hope the best for you.