1- Yes, the pump is submersible.
2- & 3- between 238-241
You have established that the problem is after the pressure switch.
Next check output of the control box. Should be about 240 across black and yellow. Some other high voltage between red and yellow.
Main winding - yellow to black; Start winding - yellow to red
You could check currents with a clamp around ammeter, or open the breaker and measure resistances. Expect very low black-yellow and higher, but still low, red-yellow.
Could be a bad pump motor or bad connection/wire.