What Causes Severe Stomach Ache In A Child?

My nine year old son has been experiencing sharp pains in his stomach for a day. He woke up in a lot of pain just a few minutes ago. He did have a stomach virus over the weekend, vomiting once, then quickly recovering. However, he has not had a bowel movement since then and has not been peeing very frequently. He says his pain is worsened by eating and drinking. He has not had a fever. He has no back pain. When I press gently on his abdominal area he says it makes no difference. He has been passing a very foul smelling gas and he says that when he burps it has a horrible taste. Other than that, he seems to have no other symptoms, but the pain is causing him to double over and to wake from sleeping. I have given him a pain medicine, gas-x, and a laxative. I m not sure what else I can do.