How have you determined there are no leaks?
You have a jet pump next to your shallow well, or do you have a submersible in it? How far is it from the pump to the tank and pressure switch ? What is the elevation difference from the pump to your pressure tank and pressure switch? How many HP is the pump?
You have a jet pump next to your shallow well, or do you have a submersible in it? How far is it from the pump to the tank and pressure switch ? What is the elevation difference from the pump to your pressure tank and pressure switch? How many HP is the pump?