Sometimes randomly after unlocking my phone or turning it on, (specifically a couple seconds maybe 4, of looking at the Home screen) I hear a noise. I'm not sure if it vibrates or not I'll check next time. But it seems to be some sort of notification that happened. Now I have no apps running but I get this beep sound. I checked text messages, emails, push notifications, battery, coverage yet its not one of those. Maybe its WiFi. But for some reason I get this random beep of the phone trying to notify me of something but it never shows up on the screen. Sometimes after locking my phone (screen being black) it does the noise. Anybody have any clue to what sort of notification this is?