Daughter with severe stomach cramps and stomach ache

Patient: My 8yr old daughter has had stomach ache almost non stop for the last 4 months. On top of the stomach ache she gets very bad stomach cramps mostly in the evenings or after she has eaten. The cramps do not start up directly after eating, this normally starts 1-3 hours after eating. And the cramps last between 6-8 hours. She takes buscopan or dafalgan or nurofen (painkillers) for the pain, but when she has the cramps this does not help.The doctors have taken blood tests, urine samples, phaeces samples as well as done xrays and echos on her stomach. The blood tests show she does not have gluten intolerance. She has done a breath lactose intolerance test and this also showed that she does not have a lactose intolerance.The blood tests did show that she has an allergy and they are not testing for food allergies as the common allergies came up showing all clear (no allergies for cats, dogs, fungi’s, pollen, grass). Currently my daughter has to follow an anti cow’s milk allergy until we receive the results of the food allergies. What I have read up on internet, cow’s milk allergy normally is paired with eczema/rash and asthma/shortness of breath,neither of these things my daughter has.Do you have any idea of what other allergy or more likely intolerance she might have ?I suggested Irritable Bowl Syndrome, but this was taken off the table as they feel she is too young to have that as well as the fact that she does not have diaree, constipation and is not vomitting.

Symptoms: Stomach ache, sever stomach cramps