image by Sema at Zazzle
Our mind is flexible and our subconscious is greatly influenced by the thoughts and statements we repeat. That's why affirmations work. It's sort of like an operating system, somewhere below your day to day rambling thoughts, there's a structure that follows a logic pattern - a pattern you've built over a lifetime of thinking.
When it hurts, I used to instinctively think "oh no, here comes the pain, this is going to be horrible" based on previous experience with pain flares. Then a friend of mine started prepping me with healing affirmations, and even though I didn't really believe in them I practiced repeating:
I am safe
I am healthy
I am filled with positive thoughts
My body is my best friend
and similar things.
Retraining your brain is just like learning to walk again, you have to start over, reboot and do everything differently. Affirmations are an invaluable tool in that process. Unlike some people, I don't think changing your thoughts is enough to change your health. Sure it can start there, but I think acting on your new thoughts is the key to positive change. Thinking positive is important, but action is key.
To help you get started you can use affirmation cards, check your bookstore to find ones that appeal to you. I just found these "Healthy body" cards by Louise L. Hay that you can even have as an iphone application with daily reminders and healing affirmations, yay :D