Well the good news is it is the right cylinder head, and not the left. It could be a bad coil pack, or a coil pack about to fail, along with a few other issues. The computer could be bad as well. What exactly did they do to arrive at the determination that nothing is wrong? Did they do a cylinder leak down test, check the plug and coil pack, check the computer itself? Just the fact that the light came on means something is wrong, the light doesn't come on for no reason. I'd start my trip home, being aware of where the next dealer is all the time. If the light comes on get to another dealer. I know how you feel, good luck!