I Just Returned From A Month Vacation In Australia And

I just returned from a month vacation in Australia and New Zealand. No problems, lots of exercise, although the 27 hour trip home left me with abdominal pain in my left side for the last day and a half. I thought it was gas from flying at high altitudes, I have had bowel movements so things are moving through my system...it just seems that I have a tender spot on my left side about at navel height. Can you help?