iPhone 5S turns on by itself

[martosprint]

I have a 3 month old iPhone 5S and it's been working fine till this morning. I noticed after I shut it down/close it after a few minutes it turns on to the homepage. I turn it off and after awhile it comes back to life again. It does this without any notifications, messages or emails coming in. Any idea how to correct this, perhaps a setting? Other than that it's fine, but I see it uses up some battery percentage.
thanks for a reply

 

[I7guy]

That's really weird. Have you tried a hard reset and/or restore?

 

[Russiaone]

Perhaps your ID sensor isn't clean?

 

[martosprint]

Thanks for the replies. Yes I did a hard reset pressing the home button and the top button. I can't check it right now because my wife has the phone and went out right now. I will check it again and monitor it when she gets back. If it still occurs I will contact Apple and get their input and see what they suggest. Like I said I re-booted it just before she took it with her and I will see if it still happens after that hard reset. Thanks

 

[martosprint]

Okay a hard reset fixed the problem. Thanks to all who responded.