You'll need to get an electrician to see if 230 volts is available in the shed and if so wire in a 230 volt circuit with a double pole disconnect so that you can run the pump on 230. Also verify that the pump is actually set to 230 volts.
have 40' from pole to shed and 50' from shed to pump. 12 gauge.
First you said it was 30 feet from shed to pump, now it's 50 feet plus another 40 feet from the pole for a total of 90 feet. Is that a single 12/2 feed from the pole to the shed as well? How much more wire between the service entrance and the pole or is the pole central metering? Is there 230 volts available at the pole?