iPhone 5s screen clicking when pressed down, a problem?

I've had my iPhone 5s since August 2014, and about a few months ago I noticed that when I press down on the upper left corner of the screen it presses down and makes a clicking noise. when I look from the side, it looks like the screen is actually moving up and down when I press hard. I was worried that the screen was going to come off, but the clicking went away. It came back a week or so later, and has been coming and going ever since. Only a few days ago I have noticed that now not only the upper left corner clicks, but the left side and lower left are clicking too. I can't stand the sound and it seems to be getting worse. Should I take it to the apple store and see if it's a problem where I need a replacement or if they just have to fix the screen or it's just nothing?