Combined birth control pills, like YAZ, that contain both estrogen and progesterone are not recommended for women who breastfeed because hormones can disturb milk secretion and decrease the milk's quality. Hormones are also secreted into the milk. Breastfeeding mothers can use mini pills. They contain only progesterone.
Cycles with ovulation usually have heavier PMS and more painful periods (dysmenorrhea). Combined pills prevent ovulation (due to estrogen) and can calm symptoms like PMS and dysmenorrhea. Mini pills don't prevent ovulation so may not help you to relief your symptoms like YAZ can do.
But anyway breastfeeding is much more important than some PMS or dysmenorrhea. When you become a mother your mother's instinct will help you to concentrate on your baby and forget all your menstruation problems.