I just noticed today that when I tap the back, anywhere from the Apple logo to the top of my phone, the back will rattle. It sounds like something may have broken off or become loose inside. It is defeinitely something that just happened today or yesterday because I would have noticed it a lot sooner if it was like this out of the box. Does anyone know what the issue might be? I bought my phone from AT&T. What kind of exchange or warranty service do they offer standard? I did not purchase issurance or Apple Care.