back pain right side below ribs

Pain in my right side just below where my ribs end?
Was on an 11 hour flight yesterday and the pain started at the end of the flight and now 14 hours later it is still there. I should have drunk more water on the flight but as it is I didnt drink that much. If lack of drinking is the cause will drinking liquids help it to go? I fly a lot and have never had this before.
See a doctor it could be a problem with your appendix?
Whitewater rafting on the Penobscot River