Sudden hearing loss in one ear, causes?

Even a very small blockage can cause this symptom. I had the same problem as you recently, and ended up having my ears "blown out" at my doctor's office. They got only a tiny bit of wax, but it did the trick. Another thing you can try is baby oil. Slightly warm a small amount, pour in your ear, let sit for a few minutes, then turn over and drain. I had swimmer's ear as a child and this worked for me all the time. Also try pulling on your ear lobe to try to dislodge it. Good luck; I know this is really uncomfortable.