my iphone doesnt react to any pc

my iphone doesn't react to any pc or usb storages, and it also doesn't charging when its connected to the pc. i want to update my ios but every time i try to update it ends up with "verifying update" and it can load this for an hours. 😀 i deleted all of my photos and there is a lot of space in my device. my iphone restarts itself every 2 hours, sometimes its logging out of my all emails, fb, messenger, instagram and etc. also from apple id. so help me, what should i do? 😟