Infant constipation

My son who is 9 month old is suffering from chronic hard, painful bowel movements. This began when we introduced solids. He is breastfed, and he eats 3 solid meals a day(I prepare my own). He strains, the stool is receeding sometimes and he occasionally has tearing. He is very pleasant otherwise and only cries when trying to pass a bowel movement.
He is very active. He does not sleep all night, has difficulty going down for naps and will occasionally wake up from a nap after 30 min and need soothed back to sleep. He has dry lips usually and is currently cutting his four top teeth. He sleeps on his stomach and had problems with gas at 3 months of age. The MD reccommends Miralax however it causes his great pain, (as does prunes and plums). Please any advice would be helpful.