I have gone through your history and symptoms.
As you are diagnosed to have viral infection of the stomach. The pain may be due to erosion of the gut mucosa , the erosion of the mucosa may be due to excessive passage of stool.The viral infection of the stomach will be associated with nausea
I would have advised
1.Oral Antacids or Rantac
2. Drink lot of water
3. If there is nausea and vomiting - you can take oral domperidone
You will be alright soon.