I have a little tenderness in my upper abdomen.... what.could b d underlying cause....?

How long? many: Don't know details. Could be gas, muscular pain, hiatal hernia (knuckle of stomach above diaphragm ), heartburn from reflux of stomach contents, but...Could be ulcer, gallbladder, colon issues, pancreas issues, abdominal wall hernia, even start of appendicitis. Ongoing? Nausea? Vomiting? Bowel complaints? Fever? Weight loss? See md if doesn't resolve shortly, any above complaints, or questions.