I am 50, female and smoke a pack of cigs a day. i tend to get small amounts of mucous in my bronchi and i make myself cough versus having to...i have allergies and every morning i have postnasal drip with thick mucous..my nose is always stuffed...i occassionally wheeze but it tends to clear with coughing ...i was able to check my oxygen recently with an o2 sat machine and it reads 94-96% sitting or standing...the problem is when i lie down it goes down to 90-94% (i can feel a little lightheaded sometimes too)...if i make myself cough,once or twice, and bring up small amts of mucous, it goes up to 97-98 but then goes back down to 94-96 if im sitting..then 90-94 if laying down, but will go up again with a couple of coughs to 97 or 98%...if i walk up and down the stairs a few times, my oxygen goes up to 98% then again comes back down....besides needing to quit smoking is this a sign of copd, chronic broncitis, asthma, emphysema or what and what is a normal o2 sat? i did have a cold a few weeks ago but it didnt turn into a chest cold just a stuffy nose with a little cough Do i need to be worried with these numbers? thank you for your time and response