Rubik,
Me thinks your 38 years of using your fingers in your ears not only damaged your hearing but your cranium contents as well... maybe it was the overpressure from sticking them in at the same time... I'd trying the "staggered insertion" method, although it may be too late.
Aircraft manufacturers deny there is an cockpit noise hazard because of the liability. Most aircraft manufacturers' and air carriers skimp severely if they "provide" headsets for the pilots. Telex is the cheapest headset on the market... guess, what most aircraft come equipped with.
:>)