I like Ang's story.
Here's a website that might give you some ideas about
testing and treating various causes of pain like this.myofascialtherapy.massagetherapy.com/trigger-points-in-the-abdominal-wall--medical-article
I had bad pain from a trapped nerve after one of my abdominal surgeries. The spasms were incredible! I couldn't get any doctor to do anything about
it, but it eventually went away.