Pooping probs

My 1 year old is having problems pooping and has been for a couple months. Whenever I bring it up to her dr she says to just use have apple juice and half water and we have been doing that for about two weeks now and her poop is still hard. And it’s huge and she’s screaming when she poops. What do I do? We’ve tried pears apples prunes in juice and solid form. We are at our wits end because she is so miserable and it hurts us to watch her scream until she passes these poops that are sizes of golf balls.