Pressure Switch
Either you have a bad or failing bladder, or the tank is very low on air. As for the pressure switch I would bet that the switch or the nipple that it's mounted on is clogged with dirt/debris. To check I would turn off breaker at the panel. Then disconnect the wires from the pressure switch and remove the wires. Then un-thread the pressure switch from the nipple. Check the underside of the pressure switch to see if it's clogged. If not I would then un-thread the nipple and check that also.
If that's the problem great, put teflon tape or pipe dope on the threads of the nipple, re-assemble everything and re-connect the electrical wiring the same way it was disconnected. Add an air charge to the tank of 2 psi below the cut-in pressure of the pressure switch. Turn the breaker back on. Pull the little lever on the pressure switch so the pump starts and hold it until it builds 40 psi or so and you should be all set.