shelly- i need help for my toddler

Shelly, I really need some help. I have a 2 1/2 year old little girl who has suffered from constipation since birth. I breastfed for one month, then switched to formula. At the age of 10 months she began to refuse the formula, no matter what we tried and has been drinking nothing but juice and a water since. Now that she is on solid foods, we push a lot of fruits and vegetables on her, which she seems to enjoy, and she drinks juice all day long. She is also very active so none of the traditional causes really apply.

I should also mention that I have been constipated my entire life. I can not remember a time that I wasnt. I can still remeber the time in grade school my father rushed me to the ER becasue ! was screaming in pain. After much tests the doctors told my dad I was "full of shit". I hadnt pooped in over two weeks. I can remeber being forced to drink Milk of Magnesium, but I don't recall whether it helped or not.

Is my daughters problem hereditary? Is it a virus, bacteria, parasite or what? The pediatrician is not concerned becasue she poops three times a week and he says that thats enough. But I see my daughter go behind the piano at least once a day to hold it in until the urge passes. If I approach her, she cries and begs me not to touch her. I am often forced to apply a little oil to he anus to get the poop out, and when it comes out it is huge!!

Please help, I can't bear to watch my daughter suffer and I know she is distorting her colon by holding it in all the time.