Ohhhhh gastric pains are such hell. Could be anything Timo. From appendex to ulcer to a darn abdominal aorta! Know I get those self same pains. Sometimes caused by gas build up....eek

Other times by my slightly enlarged abdominal aorta (always gives me a rebound pain.) Apendex out years ago. But, get it checked out man. Could be one of too many things...
Hope you get it sorted soonest.