Your daughter is not potty trained - if she were you would not be seeing this problem. I'm assuming she is medically well. If she has not been checked out, then be sure to do so. If she is OK medically, schedule times on the potty and rely on a reward system to build her motivation. If you happen to know any families who have children her age and who are trained, sometimes they can encourage a child who has not mastered the developmental task.
There is likely no medical reason for the behavior, though it's important to check this, particularly in light of her history. My giess is that you'll end up having to approach the matter behaviorally, and in that light the approach I mentioned above is the usual recommended approach. I would basically ignore what she said in response to your question. Children make an effort to explain because there is the expectation of an explanation, when in fact they are not particularly in touch with what is occurring at such a young age.
so medically she has CAH congenital adreneal hyperplasia and has has surgery to recreate her vaginia and she had reflux on the right side of her kidneys.... and had her tubes moved to fix it.. I am going to make a Dr. App, but i am just wondering if shes lazy because when i ask her about it she says i just felt like it or i don't know... is there a medical reason this could be happening?