Having severe stomach pain and i cannot stand up straight or sit up straight. fas or something more serious? pain is moving around a little burping.

Requires urgent eval: Pain as you describe has a broad differential diagnosis--including ruptured viscus(bowel), bowel obstruction, pancreatitis, peritonitis, or any other intraabdominal catastrophe . Requires a detailed physical exam, lab accessment and possible imaging. Abdominal pain cannot be appropriately evaluated by telephonic consultation. Can't assume its gas. Laying on hands is important.