wheezing and tightness in throat

About 3 years ago I began experiencing some tightness in my throat with a whistling sound on exhaling. It feels like rubberbands around my trachea.  It didn't happen very often.
Though now, the sensation is almost an all day, everyday occurence, with some episodes worse than others.  
  I am 40 years old female, non-smoker, healthy otherwise.  I have been to an allergist and have been diagnosed with dust mite allergies.  I am on Flonase and now using nasal irrigation daily. Even though my sinuses feel better, my throat continues to be a problem. I even take a Pepcid Complete in the evening in case GERD could be a problem. I don't think it is caused by anxiety, because I don't feel worried, until after the symptoms get worse.  Morning and exercising seem to be the worst times.
  My doctor says I probably don't have asthma due to good spirometry results.  Even with the above mentioned measures, I produce quite a bit of phlegm, PND, I clear my throat constantly, and I have some throat pain (not like a sore throat, though.) What can I do to make this go away?   Would Mucinex or antihistimes help?

[National Jewish]

You should have your throat examined by an ENT specialist.  The procedure is called direct fiber-optic laryngoscopy.  The specialist will be able to look at your throat, including the voice box and vocal cords.  You may also need to have x-rays of your trachea.  What you describe can come from a number of diseases of the vocal cords, including vocal cord dysfunction or vocal cord paralysis or narrowing of the windpipe, called stenosis of the trachea.