Shallow well jet pump is messing up :( ......help!

I'll start from the beginning. Pump turns on as usual, but does not turn off. I go to turn it off and it reads a pressure of 60psi (I think it is 20-40 in/out). I plug it back in, fill the bathtub until the pressure drops below 40. I watch it. It slowly gets to 40, but doesn't shut off. So I unplug it. I come back 15 mins later, and the pressure reads 70psi!! And it was unplugged.

Anybody have a clue to what is happening?

Find where the pressure switch is and the line that runs to it. Remove and clean out the line and the pressure switch inlet.