My iPhone has become my pocket computer. It has become so useful.
Last night my hardwired phone and DSL service went down. Next to my iPhone, I don't like not having internet access.
Used my phone to report the problem this morning. Then, using the iPhone, checked my emails, bought something on Amazon, then set the iPhone on the table next to me.
Went to use it and it would not wake up. I had just charged it this morning so I knew that wasn't the problem. Pushed all the buttons without success. Plugged in the charger. Nothing. Fired up iTunes, still wouldn't wake up.
Headed in to AT&T, waited around, then they did a soft reset and all was fine. I'd not heard of that so here's the procedure, just in case it happens to you.
This is for the iPhone 6s, but I think it works for earlier ones too. Not the iPhone 7 though.
Press and hold the Sleep/Wake button (upper right) and Home buttons for 10 seconds until the Apple logo appears. That's it. If the phone is OK, it will come up like normal without altering any of you data.
Almost the iPhone equivalent of Windows Alt-Ctrl-Del.
Tom