Recently the sound on my Optimus S has started acting up. Calls, e-mails, and text messages still make sound,. But media and screen selections make no sound. Also, if I'm making a phone call, I cannot hear the other person, unless I turn the speakerphone on. I've tried turning the phone on & off, doing a factory reset, and I checked to make sure that the media volume is up and that the phone is set to play a sound when screen selections are made, but nothing has worked. Anyone have any suggestions before I take my phone in to be serviced? I've only had this phone a little over a month