Okay well I have an Iphone 3g 8gb, and everyone time i press the lock button at the top, it turns off the whole phone. I have never dropped it, and I have an otterbox to make sure it's safe. Even if I dont press the lock button and I just let it sit there, it turns off by itself again. I've only had it like 7 months, and haven't jailbroken it, so is there a way that i can go take it to get exchanged?