Welcome in H.C.M.
I have gone through your query regarding chronic cough
, sore throat
and loss of voice.
As per your symptoms it appears as you were having respiratory tract
infection with laryngitis
. Since your voice had become normal by medication but dry cough is still there.
Here I would like to suggest you that you may be having either allergic or infective pathology in your throat , that should be thoroughly ruled out by clinical examination by expert hands of ENT doctor for curative treatment.