This is normal for the center panel between the doors to get warm.
There is a small low wattage heater located in between the refrigerator & freezer sections to reduce moisture from forming & dripping water on the floor.
The outside side panels also have a heat source to prevent moisture from forming.
There could a few reasons that these locations may be warmer than usual.
If your refrigerator is running too long or more than normal:
You may need to clean the condenser coils. This should be done about every 6 to 12 months. You can use a condenser cleaning brush, this comes in handy for cleaning hard to reach areas. These can be purchased at most hardware stores or you can order one with part number 20001017.
Your refrigerator may be running too long, check the door gaskets for proper sealing, especially the bottom section.
Clean the gasket surface where your door gaskets meets the metal with warm soapy water.
If your refrigerator is located in the garage or non air conditioned area, this will cause the surfaces to feel warmer than normal also.
If your refrigerator is not cooling properly I recommend calling a service technician for diagnoses & repair.