My iphone has recently been behaving weirdly. I noticed about a week ago that the lock and keyboard sounds weren't working, didn't think anything of it but now not only are they not working but now whenever I have an incoming call or text message, the screen lights up but no sound comes through. I've tried resetting my phone, changing the ringtone/message alert to a different one, I've looked at 'sounds' on my phone but it says they're all on and working. But weirdly enough the music I have on more iphone plays out fine and when I select a new ringtone/ message alert it always give me a demo, so it's not like my sound has stopped working altogether, it's just the lock and key sounds plus my message alert and ringtone. I can't find any explaination in the manual and I've tried looking on the Apple support website without any luck. Has anyone experienced a similar problem, let me know! Thanks 