My well pump does not shut off after building up pressure 20-25lbs of pressure what is wrong thanks fsherman

I don't know which pressure switch you have, If you have a20-40 ,then your switch will every time pressure drops to 20 psi and shut the well pump off when pressure reaches 40 psi . There is a 30-50 . On the inside of the cover for the switch shows and tells you how to adjust the cut in and cut out pressures >