Yes - my DT2 aged about 6 complained on and off about stomach, not feeling sick just pain in his tummy. Took him to the doctor who thought it might be constipation, which it wasn't. It went on for weeks, with varying degrees of pain and then on advice of his teacher took him to A&E who xrayed but said they thought it was pyschosomatic (spelling?). This wasn't impossible as he is a bit of a drama queen, but even so it was grim to watch.
The pain continued, but nobody believed us, even though I used to hold the phone so the Doctor's surgery could hear his screaming, when they just said it was either constipation or in his mind. Anyway, somebody suggested a homeopath and we got him some tablets which seemed to help, and after a few episodes over the next few months he seemed to grow out of them. Anyhow, about a year later I read a newspaper about stomach migraines which listed the symptoms, all of which applied to DT2! So, my non medical conclusion was that it was what he'd had.
So, if the doctor can't help, do consider a homeopathic remedy, it shouldn't/won't do any harm, and you do feel that you're helping, it does exist and can be horrible but if you think you're child has something similar don't be fobbed off.