USB Connector makes noise when in iPhone 3G. this okay

Far as I can tell, when the iPhone is connected (for power or to sync) there is a creaking or cracking noise when the connector gets wiggled. I think the metal piece closest on the screen side of the female port is making noise when the connector is touching it. Is that normal, or does it even matter? I dont think it will cause long term problems, and I got the AppleCare so if it does hopefully Im covered. I just got the phone yesterday so it seems a bit new to be making odd noises. Would rather not exchange it if I can help it.
iPhone 3G (16GB) Windows XP N/A