My iPhone 3GS has been acting up lately. The silent switch is loose so slightly touching it will cause the silent/sound alert(bell icon) to show up on my screen and it is very annoying. Also, i recently found out that applying some pressure on the portion of the screen to the left of the speaker grill will also cause my phone to toggle silent mode/ non-silent mode. Sometimes when my silent switch is set to silent, applying pressure on the screen can switch it to non-silent mode and its risky cos I'm worried it will happen in class or somewhere where i need to silent my phone. Is this a hardware problem? Can i replace it with Apple? It's still under warranty. Thanks!