I am having the same problem. I have had a upper endoscopy and every thing looked normal. Mild acid reflux so I have been taking Prilosec, which helps my stomach. My throat problem is the same as yours and my doctor have me Flonase which makes my nose clear but still having difficulty swallowing food, and my throat feels tight like I have been exercising it. Have your symptoms cleared up! Mine haven't at all.
To decrease the mucus production you can stop drinking milk. Be sure you replace your calcium and vitamin D through foods and/or supplements. I'd ask for an upper endoscopy. That's where you have an office procedure where they put an endoscope down your throat to examine your esophagus and down into your stomach. With that instrument they can examine your throat thoroughly and see if you have any growths such as polyps.