It seems your child is having constipation
. It is very common in this age.
Please do the following -
1. Let her drink more water / juice / soup. Maintaining hydration is necessary as dehydration
is the cause of constipation in many cases.
2. Let her spend more time in toilet and maintain a good bowel habit. Hard stool is difficult to pass and causes pain. Child try to retain it. It get dry and more hard. Cycle goes on resulting in stool impaction
3. Give more dietary fiber
rich foods (green leafy vegetables, whole cereals, grains, unpeeled vegetables) and less fiber poor foods ( refined cereals, white bread, banana, milk, dairy products, meat).
Severe constipation needs purgative medicines if not relieved by above measures.
If still the constipation problem persists, visit your pediatrician
. Your child needs to be examined for other causes of constipation. Treatment will be done accordingly.