macbook make clinking sound when open

I'm not sure if I'm posting this in the right place but if I'm not I'm sorry. I just notice today that when I open my macbook pro or open and close the lid, it make a clicking sound. I don't know what going out as I been extreme gently with my laptop since I use it for school. Has anyone has this problem before if so, do you know what is it and what cause it. My macbook is still under warranty so if I take it to the store, will they and can they fix it for me (assume if it the manufacturer problem) or will they think that the problem this due to abuse of the laptop (which I think no one would really want to do since they paid so much for the laptop)

I think that if the guys at the Apple Store can't detect any traces of abuse, they will repair it.