Lol this is exactly what happened to me! I went to the doctor with stomach pains, during the rule everything out they found a totally unrelated cancer, when I was being checked out by the oncologist before surgery she says.... do you know you have a heart murmur?! Finally I was like.....ok everyone stop looking! Never did find out what was wrong with my stomach.......
One thing thats weird about having a condition that doesn't show up on any tests (I also have fibromyalgia, same problem) is that you almost want them to find
something, so that it proves you're not crazy!
Of course it has to be something treatable and totally simple so that it all goes away
Don't worry you'll be fine! And don't search it on the internet!
CC