Preheat your oven to 400 degrees. Prepare a rimmed baking sheet covered with tinfoil and a rack coated with cooking spray. Set aside. In a medium sized bowl combine sour cream, cheese, and egg. Add ¼ teaspoon of salt and pepper. Add your sage, tarragon or thyme. Rinse and dry chicken breasts with paper towel so they are totally dry. Using your finger, carefully loosen the skin from the breast meat to create a sort of pocket. Spread mixture under the skin of the chicken. Rub a final coat of the olive oil on the chicken breasts and place them on your prepared pan, skin side up. Sprinkle all of the chicken breasts with pepper and a little salt. Bake for 45-55 minutes, or until juices run clear. Allow to rest for 5 minutes or so before serving. Enjoy!