7 Month Old Has Been Congested For 3 months Help Please?

My baby will be 7 months old tomorrow and has been congested for 3 months straight. Her chest and Noise. I have taken her to the doctor 3 times and each time he gave her a antibiotic per scription of a total of 5 days use each time. When she is on the med she seems better about a week after she finishes taking it its back . What should I do I Do Not want her taking anymore antibiotic . What do you think. Please only wise advise!!!