Can't breathe

I am 36 - diagnosed with Asthma 3 years ago- have had breathing problems for 6 years now. I take advair 250/50 and xopenex inhaler, acid reflux medicine and antihistimine.  I constantly feel out of breath like I am beiing choked, but when I try to get a deep breath, it does not always work.  So I get tired and struggle for air all day, every day.  I have to take a deep breath every minute or so.  I can't sleep for more than 4 or 5 hours without being woken up from shortness of breath.   I smoked for 13 years- quit 4 1/2 years ago.  feels like a 400 pound gorrila on my chest all of the time.  contantly clearing my throat.  tests recieved- Alpha 1 test- negative.  bronco-scopy 3 years ago, negative findings except some phlem.  echocardiogram- heart valves normal.   they found I do have sleep apnea.  I have been to buteyko and other breathing specialis with limited success.  I always feel like I need to bend forward slightly to keep my breath, but then try to straighten my body, realizing my posure is off.  realigning my posture helps for a few minutes. my chest x-rays show nothing that alarms the doctors such as COPD ect. but I know there must be someting extremely wrong!  I get tired, can't concentrate and can't breathe and work is very difficult.  I have asked for a CT scan about 6 months ago but doctor still has not ordered it.  This has been going on for 6 years now and seems to be getting worse.  Future seems very dismal- can't go out because of problem, social life limited and taking care of house and easy chores seems very difficult.  Will a CT scan show anything?  Should a regular chest x-ray show breathing problems?   Any help welcomed.        

[National Jewish Health]

The most important test to help in the diagnosis and management of breathing problems is a basic lung test called spirometry.  This is simple, relatively inexpensive and gives a lot of information.  A CT scan may or may not show anything.  Someone first needs to determine the extent of your problem and see if this is due to asthma or some other cause.  If this is asthma, it is most likely that a change in your medicines or a short course of oral steroids may make a significant difference.

If these symptoms continue despite further evaluation and therapy, I would suggest considering coming to National Jewish Medical and Research Center in Denver, Colorado for further evaluation.