It is possible that condition is what is known as psychogenic , or caused by your psychology, most notably experiences such as stress. Are you nervous when out and about or in public? Do you have any feelings of anxiety or mental discomfort in theses situations? This is my first thought, as you express traveling to a great many locations, many of which would likely not contain the same factor causing you discomfort. Please let me know if this has helped and we can work together to hone in on exactly what is causing you the abdominal pain.