Respected User , hi I evaluated your query thoroughly. Most important factor for criteria age is not narrated here. In absence of that I can tell difficulty in breathing relates to decreased respiratory drive for adequate tissue oxygenation may be due to decreased immunity or other hidden factors not to be shown up on all the work ups. I will suggest salient features for you which will be helping you through : * Most vital and must is regular Deep Breathing Exercises and YOGA for 30- 40 minutes a day without failure. * Avoid smoking / tobacco / alcohol consumption if doing. * Continue regular early morning walking to rejuvenate the body with fresh adequate quota of oxygen. * Do regular Spirometric exercise at home that will show up building up of your lung power day to day. * Maintain your hydration , BP , Blood sugar, cholesterol levels. * Have high protein and iron diet. * Multivitamins and multiminerals help in building general immunity. * Avoid stress / anger episodes. * Have adequate sound sleep of 8 hours a day. * Avoid exposure to extreme cold / atmosphere with much particles/pollens and if at all necessary apply mask in such cases. * Avoid high climbing without your physician`s advise. Hope this clears your query. Thanks for using Health Care Magic and viewing my answer. Regards Wishing you a fine happy healthy life ahead. Good bye and take care Dear.