I restarted my iPhone and it gets stuck at the beginning of the restore bar
My iPhone 5s won't restore
iPhone 5s, iOS 8.3
The progress bar might be moving very slowly or seem like it isn't moving. Let the device complete the update, restore, or erase process. If it's been over an hour, press and hold both the Sleep/Wake and Home button for at least 10 seconds, until you see the Apple logo.
https://support.apple.com/en-us/HT203435