He's having headaches, trouble breathing, trouble sleeping, coughing at night. I have brought him to the doctor for this and he says its allergies and prescribed Zyrtec which didn't help at all. what are the symptoms of asthma, especially in a child?

if the doc listened to the boy's lungs and didn't hear any wheezing, he knows it's not asthma. There are very distinct lung sounds in asthma so you can trust the doc if he said it was allergies. what you may want to do is take him to an allergist and find out what he is allergic to, because if he is constantly exposed to the allergen, no medication is going to do much good.