As per the details you have given , u are suffering from COPDwith Barrett esophagus
. During exacerations of COPD u will get copious amount of sputum but during remaining times u will get sticky and scanty sputum. There may another reason that becoz of Barrett esophagus , you may get the reflux of the stomach contents , that may also give that feeling in throat,
1.wash your mouth after using rotahaler with water
2.take small divided meals upto 5times to avoid reflux
3.elevate ur head during sleeping with a extra pillow.
This will help u