Green stools, abdomanal pain along with gas, not nauseus and still have aappitite, hard for me to use the bathroom sometimes.what could be the problem?

Thoughts..: Depending on how long it's been going on for, it can be infectious (like a viral gastroenteritis), inflammatory (like crohn's or ulcerative colitis), constipation (which will give you abdominal pain, but usually not green stools), or it can be related to changes in your diet. So a long list of things it can be - would be more concerned if there were fevers, blood in the stool or prolonged course.