Iphone 5c keeps freezing at lock screen?

Last night my iPhone 5c started freezing at the lock screen and whenever I would slide to put my password in it would freeze. I have turned it off and back on several times and the same thing happens again. So I went to sleep thinking maybe it would work in the morning but it still freezes at the passcode.

Turn the phone on and from the lock screen, hold the home and sleep button at the same tie for 7 seconds.