Phone randomly shuts off and won't turn on...

[kkthekitty]

I have a question I'm hoping someone here can help me with. Sometimes, for no reason I can figure out, my iPhone 5 just seems to be dead. The battery won't be low or anything, but it doesn't turn on when I press the home button, or the power button, or both buttons together like they told me at the ATnT store once. It'll finally turn on a long while later when I do that holding down both buttons thing, though.
I thought maybe it was just overheating or something, because I'd using it a lot one of the times it happened and the phone was really hot. My mom has also said that it could be an automatic update resetting my phone, although I would think it wouldn't be so hard to turn back on afterward. Does anyone have suggestions, or do I need to get my phone looked at? Is this an update thing?
Thanks!

 

[Apple_Robert]

You need to take your phone to Apple and have them look at it. What you described is not normal behavior.

 

[Freakonomics101]

It’s also hard to diagnose without having the phone in hand. It’s just like diagnosing a vehicle issue over the phone.