My 3 week old grandson is curled up in agony n being sick he can only lie on his stomach?

Needs evaluation: At 3 weeks of age, it is difficult to determine what is causing this, it could be just "gas"--but you need to rule out other causes. He needs to be evaluated to determine the etiology. Take him in for medical evaluation.

Baby: The most common GI causes of abdominal pain in this period are gas pain, reflux, constipation and having a milk protein allergy to breast milk/formula. He should be checked out by his pediatrician. You can try infant gas drops to see if it helps.

See MD: Can't really advice without having more information than you provided. Could be colic, constipation, GERD, formula intolerance or infection. I'd discuss with his pediatrician.

Seek medical help: Seek medical help (ED vs primary care) as soon as possible.

Should be seen by dr: he needs to be seen by a pediatrician or a ped er--he is only 3 weeks old and it could be serious

See your doctor: It's important that if your grandson is in a lot of pain, you distinguish bad cramps from gas or eating some contaminated food from a more serious gastrointestinal disorder. If he is in agony I suggest you go immediately to an emergency room and please make sure his Pedistrician is involved in the discussion.