Is my iPhone 5c going to get broken?

Okay so I just recently go an iPhone 5c for Christmas and I really always wanted a iPhone so much and I finally got one and I'm more happier than ever. But there's one problem. I was scrolling down my news feed and then I hear this clicking noise on the screen and I wonder what it is. It's like the screen is loose or something. So when I push on the screen around the area near the SIM card goes in, it makes a clicking sound. So I'm wondering if it means that my screen is loose or broken and that later on my screen will crack and brake. I only dropped it once, but it had a case and the phone had landed with the back part hitting the ground. So I highly doubt that's the reason. Is there anything I can do to fix this? If so, what? And will this issue prolong and cause future problems with the iPhone? Maybe I'm overreacting, but I wanted a iPhone so badly and now that I got one, I would like to continue to have it and take care of it.

Is it under warranty?