Suggest Treatment For Constipation In Children

My granddaughter went to the ER with severe pain on her side,a week ago Monday, they gave her an ultrasound and X-ray and determined that her colon was backed up. They told her to take oral laxatives., it Didnt work,. Since then she still has side pain. Only after giving her a suppository is she release a very small amount thin like linguini. I m concerned because she hasn t done anything since last Saturday.that same day she went for an office visit with her ped pa. Her pedestrian put her on Miralax. And still no bowel movement. I m truly concerned.