Fixed! Snapped dust cover in earphone socket.
I bought this little device on eBay. Makes touchscreen usage easier for those with long nails. I really liked the little plastic plug, which was given the name 'dust cover', or something, and sold as a way of keeping the dust out of you earphone socket, as well as a way of storing the pen.
Soon after I started using the plug, it snapped off in the socket, so I've been unable to use earphones for weeks.
Bright idea: tape a pin to something, heat it up and jab it in there. CAREFULLY! Allow to cool completly, then gently pull it put.