Add blueberries, 1 tablespoon of rosemary, balsamic vinegar, and blueberry preserves into a pan. Bring to a simmer and cook over medium-low heat for about 20 minutes until the liquid has started to thicken. Crush the blueberries with the back of a spoon and set aside. Preheat grill to high. Drizzle olive oil over chicken and season with salt and pepper. Place on the grill and cook for about 7 minutes on each side depending on the thickness of the chicken. Serve on a large plate and top with the blueberry relish and the remaining chopped rosemary.