Because Ken gave you wretched advice. Now, let's look at this two ways:

What is the right way:

a) 4-conductor,10-gauge or better from the Main Panel to the pump house, fused at the main by a 30 Amp double-pole breaker.
b) In a four-position 240 Volt sub-panel, one double-pole breaker at 20 Amps to the pump, using 12-gauge or better wire. IF the pump is designed for 240 Volts, and has no internal 120 Volt functions, then the wire to the pump may be 3-conductor wire, that is hot/hot/ground. Such systems are not designed to require a neutral. IF there are 120 Volt functions within the pump, you MUST use 4-conductor wire by code, being Hot/Neutral/Hot/Ground. Your pump instructions will have all this information.
c) One single-pole breaker to lighting - and there is no reason not to make this a 20 amp breaker feeding 12-gauge wire.
d) One single-pole breaker to the receptacle(s) - as above.

Ideally you will install a WR-rated GFIC as a receptacle. You may consider installing a GFIC breaker for the lighting as well. When it comes to power in damp locations, belt-suspenders-Velcro is the way to go with safety in mind. NOTE 1: WR-rated GFIC devices have a short life - I have never had one last even five years. You do test them regularly, I hope? But they are well worth that cost for safety.

NOTE 2: Well pumps have, or should have an EQUIPMENT GROUND CONDUCTOR (EGC). And this is why they do not require (and should not be on) a GFIC device as you _WILL_ get false trips using one.

The wrong way - expect the one double-pole breaker to protect everything. In my experience, under ideal conditions, properly maintained, and so forth, this will be fine 90% of the time. It is that niggling 10% that should be bothering you.

Peter Wieck
Melrose Park, PA