9 yr old, pale has dark circles under eyes, nauseous, constipated, has body pain. Anemic or celiac disease ?

My nine year old son is always pale has dark circles under his eyes complains that he feels nasues alot especially after eating breakfast he says his head hurts alot and body aches alot almost everyday his spine hurts when he wakes up dr says he has allergies he takes singular he complains of throat hurting alot maybe he is anemic or has celiac disease my mother has celiac disease too i have never been tested for it he also has trouble with constipation and pain when urinating and after like a 5 pain level what should i do ? dr says he is fine urine is fine I have been giving him a little prune juice i worry alot about him and he gets sick alot