My 16 month old is having problems with hard stool😢

Ceanna

My son is 16 months and I believe he’s lactose. He cry’s every time he poops. It’s so sad. His poops are so big. It just hurts my heart every time. I feed him fruit, veggies are a little harder. He takes Miralax and it helps him go but it seem to give him a stomachache. He was fine on Enfamil.. So please help..