I have this too, I have had it for almost four months. And I also went to the ER for it twice in the beginning. It's horrible! I take acid reflux pills daily and I actually have an endoscopy appointment on Tuesday. Still not sure if this is a acid thing or anxiety.
You just need to stay calm. What I found that helps me most is continuing to remind myself that they looked down my throat with a camera and there was nothing there. Even though it feels as if your throat is closing, it won't close! Keeping your mind off of it also helps by keeping busy. I used to always think about it ALL day long and my throat would feel like it was closing up- scary! I tried not focusing on it and it isn't so bad anymore.
Also, were you prescribed anything for the acid reflux? I was prescribed Protonix, I think it also helped a little. We can do this