My iphone went black and won't turn back on! 1?

I was walking home and i locked my screen put my phone in my pocket, kept walkin then i tried to check my phone and the screen was completelty black and wouldnt turn back on. I tried holding the home & lock button at the same time that didn't work, i tried plugging it into my computer and to my wall charger. And it still didn't turn back on, someone tell me what to do!

This happened to me too just leave it alone and let it die leave for about 1-2 days then just recharge it hope it works.