2010 Chevy Silverado Question?

Purchased a New 2010 Silverado LTZ. It has 3,360 miles on it. Have a question about a noise I'm hearing. Only when I'm on the Highway and going over 55 mph. I hear a crackle like sound coming from the pengers side up close to the windshield. I have had pengers say they hear it too, but I can't figure out what it is. Anyone have any ideas or have heard of this?