my dad had surgery in september 2008 and he had half of his stomach and a small piece of his esophagus removed due to cancer. the sugery was a success and they were able to remove all the cancer and he is suppose to be cancer free, no treatments. he has recently started to complain of his stomach is burning! he says it is on fire in there! he has some pain and he has frequent gas. What could be causing this to happen and what can he do to relieve the pain he is in?