Why is the refrigerator side is freezing food

First some fridge 101, the refrigerator/freezer models cool by directly refrigerating the freezer section and the refrigerator section is cooled when "some" of the cold air from the freezer is directed over to the refrigerator side (typically by a fan) to keep food fresh and not frozen a temperature controlling damper opens and closes to regulate the temperature of the fridge by introducing more or below freezing air into the cabinet. In older models where the freezer was on top the air simply "gravity" drained into the refrigerator cabinet, if the food was too cold you turned the fridge knob up and less air sank from the freezer to the fridge, simple but effective.

When you adjust the temperature level it controls the freezer temperature and this turns the compressor on and off to keep the food frozen. There is typically a knob or lever and some even have electric dampers that open and close to direct more or less air from the freezer and direct it to the refrigerator cabinet based on your temperature requirements.

Now that you know how it works there are a couple things to check. If the condenser coil is plugged with dust the internal system pressure will rise and in some cases make the fridge an over achiever and can chill too much so check/clean the condenser coil. Check the freezer temperature control and turn in up, also make sure the fridge temperature control setting is not set too cold.

Finally as the temperature changes around the refrigerator it will have an effect on the inside of the fridge too so expect to turn it up and down as the environment changes, down in the summer and up in the winter.

Hope the novel helps to resolve your issues.