Iphone 4s Sleep/Wake up Button Broke

Hi,

I have an Iphone 4S, and ove rthe past few weeks the Sleep/Wake up button has been getting stiff to push down, today i am no having to push the phone on a table to lock the phone.

is this something that would be coverd by the warranty (I am still in waranty)?

Or will i have to pay for this to be repaierd?