My ganddaughter is now eight months old. She has developed a probelem with having bowel movements. She will stiffen up like a board and hold he stool. She will not let it go. I can tell that her stool is not hard and that she is not constipated. She just starts to scream and tighten up whenever she feels the urge to go. Also, she passes gas with seemingly no probelm.

Please advise