Thanks for writing to H.C.M. for your query.
I have gone through your query regarding muffled voice and ringing sound in your ear. As you said that you feel echo of your spoken words.
Considering your symptoms and co-relating them I am suspecting that you are most probably having fluid in your middle ear and this situation usually arises due to Eustachian tube dysfunction
So i suggest you to take -
(a) Antibiotics- Amoxicillin
(625 mg) three times a day.
(b) Anti allergic.
(c) Steam inhalation.
I hope this will help you.