I am having a problem with the little black button on the top of the iPhone that is used to turn the screen off. About half the time, when i try to turn the screen off by pressing this button, it doesnt work. Sometimes i have to press the button 10 or 15 times before the screen shuts off. Sometimes it works the first time. Its annoying obviously because after a phone call you want to put the phone away but you want to shut the screen off so you dont make any calls by mistake. Anyone have this problem? Should i take it to Apple? Thanks for your help.