I'm running iOS7 on my iPhone 5 and ever since I did the update my phone has random moments where it becomes totally frozen while asleep. Both the sleep/wake and home buttons do nothing and all I see is black. My only option is to do a hard reset. This happens about 5-6 times a day. I use my iPhone as my alarm clock so I'm worried it's going to do this in the middle of the night and I'll end up oversleeping. Has anyone encountered this issue at all?