Talk to Gastroenterologist on Chronic Constipation ( Seems Idiopathic To Me Now)

Hello, My son is 3.5yo and has severe constipation since he was 3mo. It is so bad that we had to manually evacuate it but now as he is growing up he has fear associates with the urge to poo. It is both, less frequent and always hard. O matter what I feed him. Now even laxatives like duphalac and lexaberon similar doesn't seem to work. When he was 6mo even then I'd feed him puree of a whole big mango, strawberries, bananas, nuts in a single serving tjat could even causw diarrhea to such a young kid but he coykdnt even poop. Now he has a fissure which obv gets irritated every times he tries to pass a hard stool. Nothing has ever helped. Does he need any sort of x-ray or what? Should I see you at tje hospital?