Blocked ear!

No, not from the injection.
But I was surprised to be given a spray for my nose(!) (one you can buy over the counter) which cleared it up.
It took a fortnight.
Something to do with eustation tubes? (spelling?)

I have had this and eventually managed to be prescribed a nasal spray Dymista which they were reluctant to give me because it’s very expensive. This took quite some time and persistence but it worked eventually. It is due to blocked Eustachian tubes.

I really doubt your C19 vaccination has caused the issue. Why not ask for an appt with nurse at surgery? Or try local NHS walk in centre. Sounds like you need a proper examination with the ear scope thingy.
Could be very resistant wax?

I had a blocked ear, but it suddenly unblocked during a Pilates session! Worth a try?

Had this for a couple of weeks recently. The surgery isn’t offering ear syringes at present because of Covid so I bought ear drops and a syringe instead, Put the drops in for 5 days as instructions on the leaflet and gradually, the ear seemed to unblock so I haven’t used the syringe.

Yes, the right ear. I put it down to catarrh. It's not blocked too much but there's swishing and noise at times, as well as hearing my heart beating when it swishes.
I hold it under the shower when showering which does make a difference, but still feels as though it needs a clearout. Doesn't make any difference to my hearing. I won't poke it though.

Try warming a teaspoon of olive oil over the spout of your boiling kettle then tip the oil into affected ear if you think wax is the issue.