Suggest Treatment For Frequent Cold And Throat Congestion In A Child

Hi! my son is 11 years old. By birth he is suffering from frequent cold i.e. running nose/throat congestion. He is born in the month of June (DOB : 25/06/1999). I was residing at the ground floor, where nearby there is a garden. Initially it was okay, but now he is finding it very difficult. He cannot concentrate on studies. Once he gets up in the morning, it has to start from sneezing. His school timings are from morning. I did alopathy, homeopathy treatment, but no improvement. Are there any treatment for this.