Hello, @prelucku
Much of what you have written mirrors my wife’s experience. Many tests and imaging but nothing to fully account for the problem.

The pattern of symptoms is somewhat different but the point is that it was only when my wife had a CT scan in the midst of a protracted episode of nausea that a mid-level small bowel obstruction was found. The obstruction seems to be the source of much, if not all, of her misery. The timing was fortuitous. She was scheduled for a routine wellness examination but when she showed up with unrelenting nausea the doctor promptly sent her for that CT scan. Previous imaging absent the nausea attack failed to reveal it.