Infant Constipation

My daughter is only 3 months old and she is having trouble with constipation. She goes everyday but it is rock hard and has literally caused anal tears. There also seem to be small bumps around the anus. I thought they were hemorroids but the dr said she is too young so I have no idea what they are. I have tried water and prune juice but they do not soften her stool. The only thing that seems to work is milk of magnesia but we have to give it to her everyday in order for it to be affective and I do not want to have to do that. Also, even now that we have gotten it soft, she screams in pain once she has gone as if something else is still hurting her. I have taken her into the pediatrician and I am taking her to a pediatric surgeon on weds to investigate this further but I was wondering if anyone else has been through this and has any advise. Thanks