my iphone is displaying a black screen with a turning wheel. I've tried restarting it: volume button up and down and then 10 sec side button. It stays the same
We are so sad to hear that your phone is not powering completely on for you, cassandra44. We are here to help.
Researching this issue with Apple, we found that besides the special restart for a frozen phone, the only other option is a Restore iPhone with iTunes. This process would require you to connect your phone to your computer with the USB cord while iTunes is running.
This process will completely reload the iOS, which most likely has a software error causing that issue. We are sad to say, that this process will delete everything from your phone. If you have your personal information backed up with iCloud or iTunes, then you can reload all of your information back to the phone.
Here is a link to show you how to restore the phone with iTunes https://support.apple.com/en-us/HT201252