I also experienced tinnitus about two days after the second Pfizer dose. I had always had very mild tinnitus, noticeable only with specific attention in quiet rooms, and this was a clear increase that was noticeable in normal situations. I also had sensations of ear pressure and "fullness".
Went to see an ENT who basically said "Yeah, maybe the vaccine, weird, but we know nothing here." and offered no solution. I had a hearing test which showed a slight decrease in sensitivity at low frequencies, but still in the clinical range for "normal hearing", so there wasn't really much to be done.
In severe cases or those involving clear hearing loss, most people seem to think that oral steroids or steroid injections directly into the middle ear would be effective at reversing whatever inflammatory process is occurring and avoid long-term damage. Steroids have their own side effects, and to be effective, need to given as soon as possible. I had waited a bit to make the ENT appointment and didn't feel like my case was severe enough to ask for this.
Now two months later the ear sensations have gone away and the tinnitus is back to the mild level I experienced previously. But it was an unpleasant experience that I do not wish to repeat. I will probably avoid the booster if possible.
However, many people have also reported permanent hearing loss and tinnitus after contracting COVID. For all I know, getting the vaccine may have saved me from much more serious and long-lasting symptoms that would have come with an actual COVID infection. No way to know unfortunately.
Goddamn biology. Back to coding now.