First of all, do you have insurance?
If you do, your doctor needs to refer you to a pulmonologist if you have not been seen by one. They have LOTS of great suggestions and are the experts at prescribing asthma medications. My pulmonologist told me I should not need to use my rescue inhaler more than 3 times a week, and if I did, it was a sign my meds needed adjusting. So, get in to see a specialist.
As for exercise, do what ever you can tolerate. If walking is all you can do, then walk. Use your inhaler before a workout.
| current weight: 172.4