The Shifter by Janice Hardy (Book One in The Healing Wars), Published 10/6/2009 by Balzer & Bray (HarperCollins). Ages 12 and up.
push the pain into pynvium, the enchanted metal that can hold pain. What Nya can do is shift the pain from one person to another. When pain merchants and politicians realize this, Nya has to go on the run to avoid becoming the ultimate secret weapon.
If you like your fantasy fast-paced, filled with action, and startling in its originality, you'll love this book.