Crying before bowel movement.

My baby girl is 10 days old. I'm only breast feeding and she is not constipated. Before every bowel movement she screams and cries in pain. Sometimes it lasts only 5 minutes, others it lasts near an hour. I've read that it's due to her abdominal muscles not being fully developed. I've tried holding her in all different positions but can't seem to comfort her. Any suggestions?