My iPhone 5S after a hanging, and using wake/sleep button then, does not wake. I tried to connect it to iTunes in my PC, but it's not responding at all. Nothing works!!

When I was starting Clash of Clans, my iPhone got hanged. Nothing worked but the wake/sleep button, so I pressed that. It went to sleep and didn't be back by pressing that button again! I pressed and hold the button until the screen came but it was in that condition of hanging again. I tried the button again, after sleep, it didn't return. I tried to connect it to iTunes, but it does not respond at all. Nothing works!!

What should I do?