No sound on iPhone 4
About three hours ago, I got a text message on my iPhone, but the phone didn't make any sound when it was received. I replied, but again there was no sound. So I checked all the phone settings, made sure the phone wasn't in silent mode, made sure the sound settings were turned up, but still I couldn't get the phone to make any sound. I tried to play songs on the ipod, but no sound would come out - whether I had earphones plugged in or not. I called my girlfriend's phone, but she couldn't hear me on the phone and I couldn't hear her.
Basically, there is no sound whatsoever on the phone. And I'm completely at a loss as to what to do? I've reset it, I've plugged the earphone jack in and out a few times, and I've synced it back up with iTunes. And nothing seems to work.
Is this a known problem? And does anyone have any fix for it? Many thanks.
iPhone 4, iOS 4