K.K.
My daughter had reflux as well, and she slept on a wedge for quite a while. It was a foam wedge that had a Tucker sling over the fat end to keep her from sliding down. It was, conveniently, just the right size to fit into the pack-and-play, so we could take it with us when we traveled. They're available from the Tucker sling website (http://www.tuckersling.com/) but they are a bit spendy. I've also seen a lot of them on eBay, or you might try Craigslist. Another option is to prop up the pack-and-play mattress at one end by putting pillows or books beneath it. Good luck!