iPhone won’t shut off My iPhone 5s just randomly stopped allowing me to shut it off with the power button. I don’t understand why but every single article online says that it’s a relatively common problem and the way to fix it is a hard reset. I’ve done a hard reset three times and it hasn’t started working again. Odd thing is, after it’s been hard reset it won’t turn back on unless it’s plugged into a charger (despite it being at 78%) it will just flash the white Apple logo every 5-10 seconds or so. Does anyone know how to fix this?
Try restore it through iTunes. First of ALL you should back it up using iTunes or iCloud. If you own an iMac , iTunes app is a built one. 
If you don’t have a Mac download iTunes app to your computer and make an iTunes account. 
Then connect your iPhone to your Mac/windows PC - login to your iTunes account - back it up - when backup is complete, Restore it (there is a RESTORE button ).
This way your issue will be resolved IMO. Cheers.