11yr old son, chronic stomach pain, buscopan offers short relief, dr prescribed augmentin es600, no improvement, please help?

Try Antacids: It can be due to Acidity(Acid reflux). I would try Zantac or Pepcid for 3-4 weeks and see if it resolves the problem. If not he should get an examination done by your family physician.

Chronic pain : Need more information to help but I would recommend a pediatric GI physician to evaluate him

Difficult issue: As you have experienced this is hard to pin down. The triad of physical, emotional and dietary factors interact in any such patient. It can be as simple as acid reflux, a food intolerance , something else or an emotional issue triggered by pain. The best way to sort it out will be a workup by a pedi GI person who specializes in such issues.

Suspect constipation: Need a more detailed history and exam to come up with a more definite diagnoses. I would consult with your pediatrician first to sort things out and he will in turn refer you to GI specialist as deemed necessary.

Anxiety/stress?? : Is he having weight-loss? Fevers? Blood or other changes in his stool? If none of those “red flags” apply, in addition to a GI consult, please consider psychotherapy for your Son. stressful changes at home or school, bullying at school or on social media are all common cause of chronic stomach pain in children