IPhone 5s freezes all of a sudden and a black screen appears?

I just got the 5s but lately it's been freezing all of a sudden and I hold the lock button to turn it off and it goes to a black ( but still turned on ) screen and the apple logo appears and dis appears, and stripe lines appear for a second. I'm really afraid that this is going to happen to my iPhone alot i mean I just bought it like yesterday:< someone help me

Just go to Apple and have it replaced. That is why you have a guarantee.

If bought yesterday then take it back to place of purchase or visit Apple store

I would definitely make an appt at the apple store, sounds like you just have a bad one.