I got an iPhone 4 about 3 weeks ago, so far numerous apps crash but I put this down to the apps, not the phone (ie: instagram crashes because it's too busy etc) But recently my iPhone 4 itself has been crashing. It just happened for the third time. Not only has it switched itself off those 3 times (in the space of a week not in one day) but a second before it does, the screen goes a yellow-ish colour and there are vertical lines all over the screen. I have not jailbroken my phone or anything. Do I need to complain to Apple or is this normal for it to do every so often?