Welcome to the most accepting and peaceful place on earth.
This forum helped me through many, many times when "I'm scared" was screaming from my heart. We have all been through a lot, someone here will be able to talk directly to your fears.
Let me tell you my take: I had atypical reflux symptoms, however, the constant clearing of your throat is a symptom that is not uncommon at all. Here's an exercise that will help that: Take a glass of water and a bendy straw (yes bend-y) put the straw in the water and tip your chin down as low as you can. Take sips of the water, do several at a time. This does a couple of things; it opens up your throat and the water helps to clear the mucous or gunk that is kind of stuck up there. This allows for the rinsing of the stuff down your throat. Simple, but it works, so have a straw available and when you find you are clearing your throat, do this exercise. Courtesy of treatment at National Jewish!!)
Back to the atypical symptoms; I did not have sternum pain; it was odd that I didn't and because I didn't have pain, Dr.'s didn't realize the reflux was as severe as it was...for many people this is a very typical symptom of GERD.
I think the best thing you can do is to get a referral to a gastroenterologist; see what they have to say; be prepared for standard reflux tests, which are annoying, but not horrible.
Rest tonight, call tomorrow!