Your well pump is designed to shut off once it reaches a certain pressure. A significant leak anywhere in the well piping lowers the water pressure in the system. So if the pressure is too low, your pump won't shut off and instead will continue running all the time.

Generally speaking, if your water pump is cycling on while you are not using water, then there is either air getting into the pressurized plumbing system or water leaking somewhere. An air or water leak would cause the system to lose pressure resulting in the water pump needing to cycle to restore the proper pressure.

The pump running on is indicative of the system not having reached the correct shut-off pressure, and this can be caused by a number of issues, but check as suggested first before changing pressure switch.

Water tank pumps that stop running at random times often have overheating issues. Pumps with an internal thermal overload switch will automatically turn off when the pump exceeds a safe temperature. The pump will then start cycling again after it has cooled down.