I've had this problem quite a few years back. A doctor explain
ed that when phlegm builds up in
my throat and does not go down, that fibers in
my throat them push the phlegm upwards until I cough for re-swallow (a-hem).
He prescribed a medicin
e (sorry, I don't recall the name) that causes the fibers in
the throat to go numb, which forces the phlegm to only go down. I used this medicin
e for about a week and the problem was gone. This solution worked for me.