definitely do any stretches you can. i fractured my L4 and had to wear a back brace for so long and had to wear it 23 hours a day it sucked and i have scoliosis too so i know where youre coming from. stretching and heating pad definitely will help you out!
I used to suffer from lower back pain all the time until I guy I met in the gym introduced me to this book. It's called: "The Core Performance: The Revolutionary Workout Program to Transform Your Body & Life" by Mark Verstegen. I sometimes used to pull my back surfing so bad, I couldn't even walk. After I read this book, and followed all the exercises for lower back, my back is stronger than ever and I very rarely have any issues with my lower back. It's definitely worth checking out, I got it at Amazon.com, I'm sure they still have it. Your shortboarding days have only begun.
I've surfed with chronic whiplash for over two years. I recommend Ibuprofin/plenty of water before you go out or after depending on the length of your session. I've found that a combination of proper diet, strength training and cardio, yoga(more importantly stretching your back/neck) will give you some relief later when you're out of the water. At least it does for me. I also hang from a pullup bar and let my back stretch out that way. Still a little stiff from time to time but it's better than it used to be. One of the most important things I tell myself when I surf is to not tense up and relax while I paddle. Hope it helps.