I've been getting muffled hearing and ring constantly for these past years and it could last up to 5 days or 3 days if I'm lucky. I'm 22. I've notice when I finish having sex/masurbate I get ringing in the ear coming up slowly and then muffled afterward. Another thing I've notice the deeper the muffled hearing is the louder the ringing is. Sometime when I feel hot (redness in cheeks) while lying down on my bed it also occurs then?
You really should see your GP for advice. If for nothing else but to reassure you.
Doctor? They don't really know that field. 
Yeah .. talk to your doctor and ask to see an ENT.
As a retired medical secretary i can assure you that they certainly do. Also there are many different avenues that they can help you with.
The doctor I went to don't really know what to say or give advice. They refered me to ENT which I guess is the best option. It just when I get muffled hearing I also get ringing too. Hopefully they'll help. 
Good to know you used to be a medical secretary. =}