My orthodontist told me to chew a half stick of sugarless gum to help with the pain from movement, but I really don't like gum. On my ortho's website, I noticed a banner ad for a place to buy supplies: wax, pain relief gel, etc. One of the products they had was something called a bite wafer. I purchased three of those, and they've helped tremendously. They are also flavored if you're into that: cherry, grape, and bubblegum.
It's been a week now, and the pain is pretty much gone from my back teeth. My front teeth are still sensitive, but those are the ones that will have to move the most.
Oh! Wax has definitely been my best friend. Right out of the gate the hooks on my back brackets were causing me grief. I stupidly tried to tough it out the first day and wound up with a canker sore. Now, I'm liberal with the wax.