Yeah, I have post-nasal drip too, and it really does irritate the throat! The doctor you saw doesn't know what he's talking about. I have some other tips that I thought of:
1.) cough drops, the sugar free kind and sugar free hard candy are good to suck on when your throat hurts, but watch how many you have because they can cause you to have a stomach ache or intestinal bloating and even diarrhea. You have to see how many you can have. My mom can't have any, but I can really eat as many as I want.
2.) alcohol-free throat spray can numb the throat really good, that might be good to help you sleep, for instance, or if you know you will be talking.
3.) sometimes you develop a little infection in the throat, and gargling with warm salt water a few times a day can clear it up. You might find it even helps with the post-nasal drip, on a more regular basis. It's a natural remedy, so it's safe to use.