Hi R. - just yesterday I visited a pediatric nurse practioner who specializes in urology and elimination concerns because my almost 4yr old has been resistant to potty training. She diagnosed him with constipation saying that even though they are having a bm every day, they have these hard sections of fecal matter that dont clear and the waste just goes around them. I think it's a really good idea to set an appt. with your doctor.
The NP/PA that I'm working with suggested a course of Miralax along with some other things to break up the hard matter and get the bowel working properly again. She said when the bowel becomes distended like that, the autonomic squeezing motion that moves things down the bowel stops working as effectively as it should so it needs a small amount of a stimulant laxative for a limited period to train it to squeeze as hard as it should naturally. Miralax is apparently very safe and isnt absorbed into the body.
If your daughter is getting a lot of fiber, she also needs a lot of plain water. An easy calc is to take her body weight, round up and divide by 2. So if she weighs 40 lbs, she would need at least 20 oz of water in addition to her other juices, milk, etc.