My Name Is Jo-Ann Tebault - I Just Turned 67

My name is Jo-Ann Tebault - I just turned 67 and I continue to work full time as a Medical Credentialing Specialist. Primarily I am very healthy; no high blood pressure, no diabetes. I do take Metoprolol Succ ER 25 mg tab 1 daily, for about 5 years.
What I do have is a constant chronic cough, which I have had for about 8 years. Nothing seems to work,
nor can any of the physicians I've seen seems to know definitively as to what I have. I first saw an Allergists. He placed me on Claitin and nasal sprays. After that didn't seem to work, he went in the direction of thinking I had Slient Reflux. After treating me for it, he saw where I was any better and concluded that I did have the Reflux. He had passed away. I seeked the treat of a 2nd Otolaryngologist The 2nd doctor said I did have Slient Reflux, he teseted me and prescribed meds for Reflux; the coughing didn't let up. He insisted that's what I had. With him having his own agenda promoting the Slient Reflux. I then went to an Allergist. He was suprised and puzzled that I have had this problem for quite a long time with no relief. He introduced me to the Neti Pot, and put me on the same medicine regiments as the 1st Otolaryngologist. After seeing that that was working, he suggest I see a Pulmonologist, I did. He conducted several Pulmonary tests-(keep in mind I have had TB tests which I must have for work; all have been negative) and chest X-rays.
Within the last 2 years my Allergist said I have the Asthma cough; I take the Advair HFA 115-21 MCG/ACT & Montelukast Sod 10 Mg ( I only stopped taking the Montelukast 3 wks ago)
My Allergist as that I see another Otolaryngologist, I did and he could say why I was coughing so much and without any relief.
I pray you can help me.