Kenmore Refrigerator not that cold.

Question

Relatively new (4 yrs old) kenmore side by side does not keep icecream and other freezer items all that cold. Also, top shelf on regrfigerator side does not keep liquids all that cold. I recently brushed and vacuumed the coils but still not working all that great. Does it need additional regrigerant or is this something more serious?