Hello Sophie_willls2,
Your two issues may or may not be related, so I'm going to provide information for both. If your iPhone freezes or restarts on its own, first back it up:
iCloud: Back up your iOS device to iCloud
https://support.apple.com/kb/PH12520?locale=en_US
Then try these steps:
- Connect your device to a computer and open iTunes. If you don't have a computer, you can borrow one, or go to an Apple Retail Store or Apple Authorized Service Provider for help.
- While your device is connected, force it to restart. Press and hold the Sleep/Wake and Home buttons at the same time. Don't release when you see the Apple logo. Keep holding until you see the Recovery mode screen.
When you get the option to restore or update, choose Update. iTunes will try to reinstall iOS without erasing your data.
iTunes will download the software for your device. If it takes more than 15 minutes, your device will exit recovery mode and you'll need to repeat steps 2 and 3 again.
If your iPhone, iPad, or iPod touch doesn't respond or doesn't turn on - Apple Support
https://support.apple.com/en-us/HT201412
Charge your iPhone and iPod touch - Apple Support
https://support.apple.com/en-us/HT201569
Take care,