I am curious about normal reactions to pooping in infants and toddlers.

My son is 11 months and for 3 months has been screaming with every poop. I know it is psychological because we got medicine to help loosen the stool(all the juices, fruits, and peas in the world would help for maybe a day)--and after a few days the medicine stopped helping! And then he was back to screaming.
(He now has an anal fissure but technically not constipated--at least not as far as the pediatrician is concerned.)

I wonder if it is normal at this age to hold it and then create painful poop for the future. My MIL and mother both said this is about my son's "determined" personality, and they are both "not surprised given you and your husband."

He is still in diapers. I am wondering if elimination communication would help.... or if this is just a stage.

I don't want him to grow up thinking that pooping always hurts. That would make potty training a nightmare!

What did your infants/toddlers do as they became aware of their ability to hold off pooping?

(I don't know if this should go in baby health, diapers, or potty.)