Welcome to HealthCare Magic. Thank you for posting your query.
I can understand your concern.
Do not worry if it is for a day or two .
It might be due to anxiety.
If it stays for > 6 months ,it could be hinting towards 
Irritable bowel syndrome.
 It is difficult to make a pin point diagnosis without actually examining you. You may need an upper GI endoscopy and a 
colonoscopy to help the diagnosis part.
If it does not go away in a week, I would suggest you to
-     Drink loads of water
-     Avoid oily,spicy food
-     Have a diet rich in fibres
-     I would start tablet 
Pantoprazole and tablet 
Domperidone. 
-    I would also start tablet Colospa (
Mebeverine).Your doctor can guide on the exact dosage
- Get a blood 
haemoglobin , total count ,Liver function test , amylase , lipase, urea , 
creatinine , ESR done 
- Get an abdominal ultrasound , an upper GI endoscopy and colonoscopy done. This will help in the diagnosis.
I would also suggest you to visit a physician . He/she can examine you and correlate clinically.
Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. 
Wishing you good health.