Place the lemon juice, olive oil, and garlic in a ziploc bag and add the chicken breasts. Seal and flip the bag around a few times to make sure all of the chicken is coated in some of the marinade. Place the bag in the refrigerator for 30 minutes.
Preheat your grill to high. Remove the chicken from the marinade and salt and pepper both sides. Grill for 4 minutes on one side and then flip and grill for another 3-4 minutes or until chicken is cooked through.