I have been having a similar problem when all my widgets (weather, book progress, etc) would stop updating at the same time. Sometimes it can go all day before they freeze, and so far, the only solution that I can find is to restart my phone.
I have a Sprint Galaxy S3 with the stock Jellybean 4.1 firmware. I have not tried rooting or installing any custom recovery on this phone. But suddenly my phone started boot looping when it gets to the Galaxy S3 screen. I am unable to get into recovery mode, but I could get into download...