Unable to eat. That i can consult.

My son is 5 yr old,since birth hardly he had mother's milk, as he used to vomit in couple of minutes, when he used to sleep,couldn't see the testis on the right side, when he used to stand we could see the testis and he used to complain of pain around the testis, consulted many doctors in Hyderabad no one said what is the issue, finally whilst I was in my native place in Ballari,doctor said that my son needs operation at the earliest,as he has hernia, in Bengaluru got him operated,I could see there is an improvement in eating,still the vomiting did not stop, unlike other kids, I have never seen my asking for chocolates or ice cream or fruit juices or food item that he likes,don't know what is the issue, a week he eats normally, next week again the same continues vomiting, even now we force feed him,can you please help me, how this can be cured or any doctors that I can consult.