Sounds like
you might have a mild case of
allergy related athsma. Try taking an
allergy medicine for a week and see if that helps. It doesn't sound like you have any mucus, so the cold medicines wouldn't work. My children have allergy related athsma. They rattle when they sleep and mostly just when sleeping or exercising. They also have a cough. I even had one child who always sounded like her nose was stuffy and had bad breath, that went away with the allergy medicine.