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.