Hi Patsie,
I have similar but slightly different symptoms than you.
Had a really bad sinus infection 18 months ago and since then have had ongoing issues with post-nasal drip, scratchy throat and blocked / popping ear (audiologist diagnosed mild eustachion tube dysfunction).
I have seen 7 different GPs and told different things. Most prescribed steroid/antihistamine nasal spray whereas one told me to stop it completely. Another recent GP told me to try a new steroid only nasal spray and also prescribed Lansoprozole to address any potential silent reflux (which I think I have). 2.5 weeks later I was back to another GP who diagnosed a nasal polyp (previous GP did not diagnose this despite looking up my nose) which would explain symptoms. He said to stay on steroid nasal spray to reduce inflammation/polyp and stop the Lansoprozole as he thinks polyp is causing post nasal drip and related symptoms. He said to try one thing at a time which I kind of agree with. If nasal spray doesn't work on the polyp then he will prescribe a course of oral steroids to treat it. So far (12 days later) the pnd and throat seems better but I still have some fullness/popping in my ear. He said to give it 6 weeks and I have booked a follow up appointment with him.
If you have had an ENT appointment they would have spotted any polyps so that is good. I think I may have issues at both ends - nose and LPR but just going through process of elimination. Could you try a course of PPI's from GP to see if they help?