Well from the description of your symptoms followwing are the plausible cause in descending order
1. Eosinophilic Gastritis
will be required by gastroenterologist.
2. Parasites .... stool test
will show us , but usually stool tests are normal.
3. IBS ( irritable bowel syndrome
) mostly seen in autoimmune diseases like hashimotos.It is a diagnosis of exclusion
4. H.pylori infection , with pain in upper abdomen.
Hope this helps