From a natural perspective (which I am guessing you may be interested in because of your profession) your daughter has classic signs of an upset gall bladder/liver. At her age the cause would be one of three things. She could simply have a stomach bug that her body is processing and working on eliminating. Another cause could be if you are having emotional upset and she is picking up on it and it is manifesting physically,.....or she is eating something she is allergic to and it is putting stress on her liver and therefore her gall bladder (which was the case with my son). Other signs of food allergy include dark and/or puffy circles under the eyes, a "target" rash around her anus (just red around the anus), rashes, exzema, ADHD like behavior after eating certain foods, a constant cough or runny/stuffy nose, etc. If this is the case there are some simple things you can do to get her back in balance. First you can get allergy tested--I went an alternative route and got EDS (electral dermal screening). It is a non-invasive test that will take about an hour and leave you with no questions. Then you make sure you don't eat those foods and neither does she. Also, with a gall bladder, anything with a high level of fat will stress the gall bladder and make the problems worse. We did allergy elimination treatments on both my sons and did some natural remedies to get them back in balance.
In any case, some foods that are good for balancing the gall bladder are beets, carrots, artichoke, dandelion greens, olive oil, garlic and high fiber foods. There are also some homeopathics that might help. I'm happy to go into this with you further if you feel it is something you want to pursue.