My son is 6 and has dealt with constipation for his entire life. Even if he has a BM every day it is still hard. He does eat very well. When we put him on miralax he seems to soil his pants. When we put him on fiber such as metamucil it seems to make the stool bigger. I do not want him to have a fissure like me. But trying to find a balance with him is hard. He does he fruit and veggies, he even likes prunes.

Melissa,
not sure if this will help but here's my daughter's story.
My daughter won't eat her veggies or even fruit. But I make her chicken soup from homemade stock almost every day for lunch. I sometimes wonder if the gelatin in the stock (I simmer it for at least 8 hours) keeps her regular, because the only time she gets constipated is if she isn't drinking enough water.
She wouldn't drink water at school, so now I send her with a full water bottle every day and she is to drink it or we sit out front of the school til she does. She understands the importance now, after getting a fissure before Christmas. Freaked me out because of my AF and my mom had one a couple years ago. Don't want her to go down that road so too!.
Every day she drinks a tall glass of water before she goes to school, the bottle at school and a tall glass of milk after school, and another tall glass of water before bed.
She eats brown rice now instead of white, whole wheat bread and I get a pasta called 'smart' pasta by catelli that is fiber boosted with inulin.
But still, no veggies or fruit. But even so, things work well for her now. I also taught her to lean far forward when she has a BM so it comes out easier.
Hope this helps! I know how stressful it is. I mean it's one thing for us to suffer, but not our kids too!!
-Tanya