Suggest Treatment For Shortness Of Breath And Sneezing

I have a boy 6 yrs 8 months old ( 25 kgs weight).When he starts to sneeze he continues for 5 to six times with white thick nasal discharge coming out after two or three discharges.This condition is present in him for about three years.Of course, this does not mean that he sneezes frequently.But when he starts to sneeze it does not stop quickly.Three years back once when he had fever with cough and cold he started wheezing particulary after repeated coughing.So far I have seen four episodes in him with rougly eight months to one year gap between each episode.During the second and third such episodes he also complained about slight pain in the chest muscles and shortness of breath.During the first episode I took him to a pediatrician who told to my shock that he may have Asthma.He asked whether anyone in my family has it or not.My mother developed Bronchial Asthma at the age of 45+ due to over load of work and climbing of stairs and also because we used to have pet dogs and later cats in our family.She is still having the same problem.However, now netiher we have any pets in our house , nor there is any chance of vehicular pollution or cigarette smoke.I don t know how my child could get asthma.The doctor gave salbutamol to him and some antiboitics also.But I did not give the salbutamol tablets to him fearing that once it is given it may permanently damage his lungs.During the second such episode after about one year.I took him to my company hospital where the doctor suggested to give nebulizer with asthaline for 5 minutes.This time I obeyed and my son told that he felt releived .During the third time also as per the advice of our Company s doctor I gave him nebulizer for 5 minutes .Recently, he had fourth such episode after about one year gap.This time the doctor sggested nebulizer for 5 minutes at Hospital and also 2 salbutamol 2 mg tablets daily for five dyas along with Cefpodoxime 100 mg for 5 days ( 2 daily).When he was a small baby we used to keep him near to our closed wodden window as our bed was situated near the window) during sleeping after covering him with sweater and all other precautions during cold seasons.Is it that due to exposure to cold her lungs got damaged.The place where I used to work then used to get very cold during cold season.Anyway I used to keep a room heater below him also.Please confirm whether my child is asthamatic or not.Earlier to this episodes I used to give him cetrizine cough syrups on some occasions when he had cough and cold.