First, I hope your dd starts to feel better soon. I'm glad you're having an eval.
With "cramps", what causes the discomfort is
prostaglandin synthesis, and yes, ibuprofin does help with that, but the key is to take it before the onset of menses to help with the inflammation that they cause. So if that's what it was, you were on the right track where she hasn't menstruated yet (but maybe she will be soon). However, with ibuprofin, you do have to make sure that taking it doesn't cause GI bleeding, so you only need a small, regular (ie round the clock) dose, with food. If this is what the issue is for her, she'll learn what dosing works best. I had such horrible menstrual pain when I was her age, I wish we had something as good as motrin, all I had was midol and it was useless. I remember going to the doctor, too, for it and yup, he said it was "cramps". I still have horrible pain sometimes and my motrin works wonders, thankfully.
Another thought. My DD 10 had been complaining off and on of stomach discomfort. I finally figured out she has a late onset allergy to lactose, and it comes and goes which our pediatrician says can often happen. So that gets kind of tricky. She loves dairy so she takes the pills before she eats it and she's ok. Once in a while she forgets and eats an ice cream or something and she winds up with an upset stomach. But she's learning how to manage it.
Another thought, as I think someone else mentioned, would be GERD, for which a PPI might help.
Good luck.