iPhone 7+ text message with no contact or text but location is on?
This could be a corrupted Messages database. If you have your texts set to expire after a certain amount of time (under Settings → Messages → Keep Messages), your message threads would normally get emptied out, although the number would remain at the top.

You can find out for certain whether you’re sharing your location with anybody by going into Settings → Personal Profile (at the very top) → iCloud → Share My Location. If the list there is empty you should be fine, though you might still want to Stop Sharing My Location to see if an error/change occurs.

The Personal Profile submenu exists in iOS 10.3 and later. Otherwise just directly scroll down to iCloud after opening Settings.