By your query I came to knew that you are having sore throat
with pain in ear and you are already under treatment of your doctor, who had diagnosed as a case of Eustachian tube dysfunction
Since your ear is clogged and earache is with sore throat these findings favors for above diagnosis, but as you said that your mouth opening is also painful this symptom directs us to consider inflammation of jaw joint (TMJ) as well. Some times the inflammatory pathology of jaw joint give rise to pain in ear this is named as referred pain
Here I would like to tell you please add these in your present treatment-
1- Anti inflammatory like diclofenac
2- Anti histaminic.
3- Steam inhalation.
4- Soft diet
I hope this will help you.
Thanks for consulting H.C.M.