What Health Condition Causes Cough That Lasts For Eight Weeks Despite Taking Cough Syrup, Prednisone And Codeine?

Question: I have had for the last 8 wks a cough that will not go away. It feels like it is deep inside my lungs, like something is grabbing my lungs. I have seen a doctor 5 x's so far. They have me taking prednesone, cough syrup w codeine, a breathing machine w a steroid including the nebalizer med. to no avail. Can this be an infection , I am getting real worried this is turning into something serious. I almost went to a hospital today because the pain in my lungs is starting to hurt on the sides of my lungs also. Any suggestions?
I have had an xray but it did not show anything at that time. No one has taken a blood test or given me antibiotics on a regular basis.

1) I do not have a fever 2) At this time I do not have any phlegm when I cough. lt is just a dry cough that feels as it is coming from deep inside my lungs. 3) No blood staining or yellowish discharge. 4) The xray I was given was about a month ago.
5) Yes, the pain I am experiencing in my lungs does feel worse when I can breath deeply. I almost felt the need to go to the hospital today because now the pain is growing much more like the outside of my lung is also hurting. I decided to wait to hopefully get a much better understanding after getting another view from another Dr. 6) I do not have any history of asthma but twice I have had pnumonia. 7) I do not know if I was ever in contact with someone that was diagnosed with tuberculosis. I just know in Dec.(2017) I was at an inside rodeo and there was an elderly man that I noticed was sick. He sat next to my grandson and I was two seats from him. The next day I was sneezing, coughing and saw my Dr. to try and ward off possibly the flu since it was getting rampant. My grandson became sick to the next day, but by the end of the week he was better. Since Dec, I have been to the Dr. 5 xs. They even gave me a flu test but it was negative. I have been battling this cough since then. 8) I have never smoked. 9) My other concerning symptoms is the feeling as something has a grip on my lung and I can't get a deep breath without coughing, the pain in my chest that just rubbing my skin on the outside hurts and it seems to not be getting better, possibly worse. And of course the weeks that I am still having this problem after doing everything I have been told to take and not getting well. 10) I am taking other prescription medicine but have not been taking it regular because it is hard to swallow. a)Losartan Potassium tab. b)Metformin 500tab. c)Myrbetriq 25mg d)Omeprazole 40mg. e)linzess 145caps.