iPhone 5 unresponsive touch screen

I’ve had the iPhone 5 now for a little over a week and found the screen to act unresponsive at times. For example, I have noticed that it commonly occurs when I enter my passcode. One of the numbers usually won’t register and I have to go back and retap the digit. It also occurs when I hit “Install App” or “Send” on a SMS. I hit it once and nothing happens, sometimes twices before it registers. Has anyone else had a similar problem? What would be the correct course of action to bring this to Apples attention? Thank you.