I have a question regarding how asthma is diagnosed. Here is the context.

I have had no problems with allergies or asthma throughout my life (~ 40) so
far.
I quit smoking about 8 months back and ever since I have developed shortness
of breath which I never had before.
It is not as bad as if I really need emergency treatment...if my mind is
onto something else I forget about it.
Sometimes I think its psychological since there would be stretches of days
when I won't even have it, but it will
return again after sometime. My doctor thinks that it is asthma and has
prescribed inhalers (advair 250/50) and
cough medicine like promethazine/cod. I have bought these and keep them at
hand, but have still not taken any of this...
I do not like to take medicines and plan to take it only if I find that I
absolutely need it.

BTW, I regularly exercise and have no problems doing cardio-vascular
exercise for 1 hr at a stretch. Sometimes I have shortness
of breath after doing weights. But I remember at least one occurrence of
shortness of breath when I was not exercising for
over 2 weeks, so I cannot really say that exercise is the cause or I have
exercise-induced asthama.

The last time I visited the doctor I asked him if he thought it was asthma
or COPD/emphysma. I had a breathing test early
last year which was normal, and the doctor said that he sees COPD with heavy
smokers over 45 and so he does
not think it is COPD. Nevertheless, he gave me a sample of Combivent
inhaler, which I believe is used to treat COPD.

I am kind of confused as to whether I have asthma or COPD? I guess if
Combivent is used to treat asthma too, then the doctor is still
treating me as an asthma patient. But why give me a COPD medicine if I have
asthma? What are the symptoms of asthma?

This was over 3 1/2 months back. I still have'nt taken any medicine. The
shortness of breath comes and goes especially when I
think about it. For example, recently I was on a plane for 3/4 hours (the
first time on a plane since I developed this shortness of
breath) and I was having difficulty taking a complete breath. I think having
it on a plane is more psychological, because I was
apprehensive about spending cooped up on a plane with shortness of breath.
But I have a very
long plane journey (15/16 hours at a stretch) coming up towards the end of
this month, and I need to prepare for it. Basically I need a
fall-back medicine that I know will work quickly if I am in a panic on a
plane.

I had another (previously scheduled) breathing test done last week. This
time I had to take a medication (inhaler) before completing the
test because the nurse said that one of the initial readings was less than
expected. During the previous test I had no problems. The only
difference is that during the previous test (10 months back) I was still
smoking and now I am not. I am scheduled to meet the doctor
about the test results next week. Let's see what is the outcome.

I plan to take combivent and see if it can 'fix' by breathing problem when I
have it, so that I'll be psychologically ok before
going for my trip - knowing that I have my 'fix' at hand if I think that I
cannot breathe properly while on the plane. Meanwhile I  just wanted
to ping this newsgroup with the following questions:

1. Is there any other medication that does a quick relief of shortness of
breath?

2. How is asthma diagnosed? Is it done through breathing test? Is there a
psychological part in it that makes you 'think' that you are
short of breath?

3. Is Combivent a good medication for quick relief? I would rather take that
instead of AdvAir, which I have to take 2 times a day
indefinitely it seems...and I do not think that I am really in need of that
kind of extended medication. After all I have survived almost
8 months without any medication.

3. What does breathing test result indicate? It is just the capacity of the
lung right? Is there any links that I can read up as to what
are the test metrics, what are the normal results etc?

Thanks for any help.
Shantanu Sen