These past few days, my iPhone will ring several times a day as if I have a new text message. And I don't. (It's the text msg sound). Usually, if there is a new message or notification of any kind, the screen will light up and the blue message screen will appear to tell you what it is, but this just stays as a black screen and no message at all. Anyone knows why? I already tried restore to factory setting and re sync it again, but it still happen. I also turned off all the notification alerts from my apps.