You can check a few things. First, as odd as this question may seem it has happened to many people so it doesn't hurt to ask...did you remove the plastic covering from the front of the device? If you haven't then you should. Although some like to keep it there as a screen protector it is best that you invest in an actual protector rather than try to use the shipping plastic. If that's not the issue, have you been using earphone in your device? Try plugging in the earphones and then taking them back out. Some have mentioned an issue where the phone may still think the headphones are still plugged in. You can also try the usual suggestions...reset/restart/restore your device to see if that fixes the problem. If none of that works, then visit your local Apple store if available and have the Genuis Bar take a look to make sure you don't have a defective device. You can also visit a VZW store or call tech support for additional troubleshooting. You can find the full owner's manual for your iPhone on the Apple support website (the link used to be in my signature but since the forum has changed I'm not sure if it's still there. Just go to Apple.com/support and you should be able to easily find it).