I am often in exactly the same situation... and with me it's the eustachian tubes which block either die to mild infection, a kink, or more often than not it's snot getting blown into the tube when blowing my nose. I've been told and told to leep my mouth open if I blow my nose, but I keep forgetting....
The medics won't put in grommets in adults around here... but both our twins had grommets twice due to middle ear infections (that connect to the eustachian tube for pressure equalisation).
Menthol crystal inhalations help sometimes..... but you sound as if you have sinus problems too.
And as for the tinnitus.... have you tried identifying the exact frequency, making it into a sound file, then blasting yourself for a few minutes? I do that occasionally and in my case it works... silence for a short while.
I used
http://www.nch.com.au/tonegen/index.html to identify then duplicate the tone......