I am a 5-10, 175 lb,32 year old male in good health.  I am a military pilot with frequent physical and medical examinations.  About 4 days ago, I got a pain in my upper abdomen that I can only feel when I am up walking around.  When I sit down, or when I lay down the pain subsides.  It feels like a side ache, due to running or walking after a carbinated beverage, but it usually occures after about 25-50 steps.
Hello Most likely pain is related to musculoskeletal reasons, but other causes like liver, gall bladder, renal pathology etc. should be ruled out. You need proper clinical evaluation and investigations. Basic investigations are routine hologram and ultrasound of abdomen. Ultrasound of abdomen can exclude many possibilities. Proper treatment depend upon findings. Get well soon. Take Care Chat Doctor.