Most like it is from the constipation. Maybe cut out wheat and dairy to see if it changes things. Something could be binding her.
I have had bowel issues since I was little and I am 35 now. I get odd blood and mucus in my stool often and I have colonoscopies done but it has always turned out as nothing wrong.
I would take her to the pediatrician just to be safe. When my daughter was like this she gave us this powder stuff I think it was called PEG3350 or something like that and it is a white gradual kind of like a laxative but it isn't habit forming and it gets things moving.
yeah.. every time she poops she pushes n pushes until it comes out,
Has she been constipated?