Freezer is over-freezing

Most have 2 controls in the refrigerator side. 1 is a thermostat or cold control the other is a air damper. the damper allows the flow of air from the freezer to the freshfod side. if it is closed all the way you are keeping all the cold air in the freezer and that will make it colder. most cold controls monitor the air in the fresh food section and regulate the temp. and some controls are confusing and the damper actually works in the reverse of what you think. but if the unit is always running you may have a bad cold control and it is sensing the temp in the refrigerator side is not col enough, so it will continue to run until is can be satisfyed. check the control to make sure it is shutting of if you turn it up. if not I would replace it. I dont know how old the unit is but you also may have some electronics that control the temp to.