Could you get carpal tunnel syndrome from masturbating?

Unlikely: Carpal tunnel can happen after to people who are involved in repetative activities but unless that activity goes on for several hours a day every day it is an unlikely cause.

Carpal Tunnel: It certainly is concievable if your wrist in the wrong position and you are doing this for prolonged periods.

Maybe: Many times the exact cause of carpal tunnel is not determined...Some people just get it. Some repetitive activities (usually associated with vibration) can cause swelling within the tendons of your carpal tunnel, which may increase pressure on the nerve involved. This may relate to frequency/duration of masturbation. Stop masturbating and see if your symptoms improve.