stethoscope symbol find my mac, what does it mean and how can i turn it off?

From what I can find, that means that the device has been put into "Repair State" so it could be sent in for service without actually removing it from Find My. As of the last information I can find, there is no way to change the state of your iPhone manually, though if you contact Apple Support, they may be able to tell you how to proceed.

Regards.