For no reason my iphone won't wake up after I went to the kitchen to get some food. The last thing I did with it was playing phoenix HD and then removeBG before I locked it. When I come back, it won't wake up when I press the home or lock button, I then searched google(meanwhile, the respring icon appeared and stuck there forever) and tried holding the home+lock buttom, it worked, fortunately. But it was quite scary, is this common and does it indicate there are problems in my iphone's hardware/software? Thanks.