Hey Owinoc,
Thanks for the question. I understand that you are experiencing issues with Personal Hotspot since upgrading to iOS 7.1. The following resource may provide a solution:
iOS: Troubleshooting Personal Hotspot
http://support.apple.com/kb/TS2756
Basic troubleshooting
1. See if your iOS device, computer, and wireless plan all meet the system requirements for Personal Hotspot.
2. Make sure Personal Hotspot is on: Tap Settings > Cellular > Personal Hotspot.
3. Check the Internet connection on your iOS device: Tap Safari and load a new webpage.
4. If one connection type doesn't work, try another. For example, instead of connecting using Wi-Fi, use USB or Bluetooth.
5. Turn Personal Hotspot off and on: Tap Settings > Personal Hotspot or Settings > Cellular > Personal Hotspot.
6. Install the latest version of iOS.
7. Reset your network settings: Tap Settings > General > Reset > Reset Network Settings.
8. If you still see the issue, restore the iPhone.
If you're still experiencing issues, try the steps below. […]
Thanks,
Matt M.