Hi and welcome to our forum!Although there are reports of individuals experiencing shortness of breath due to the presence of large breasts, it is an unusual complaint. Individuals usually complain of neck pain, back pain, shoulder pain, bra strap grooving, and chronic rashes beneath the breasts as well as a stooped forward posture.If your symptoms are caused by the weight of your breast compressing your chest when on your back, there may be a degree of relief with breast reduction. On the other hand, intrinsic asthma will not be affected by breast reduction as it is caused by airway constriction due to inflammation and swelling within your lungs.Seek advice from your primary care physician whether it would be worthwhile to undergo this procedure to improve your respiratory symptoms. Best wishes...