Large majority of issue should be fixed by getting rid of corrupt plist file, com.apple.Bluetooth.plist then hit restart.
If it does not work, you might want to try reset SMC following instruction for your machine.
https://support.apple.com/en-us/...
If that did not help, get your warranty or apple care info ready as, you might want to make reservation at genius bar at nearby Apple Store, since you might actually have hardware issue.