Deane, what you are experiencing is Tinitus. This is usually caused by exposure to loud noises, such as gunfire, explosions, overly loud music, etc... I've had it since age 17 when I was a first loader on a 3-inch, dual, anti-aircraft gun with no ear protection. (Navy didn't offer ear protection in the 1950s)

There are at least 2 over the counter drugs that can help, but after a while they tend to be less and less effective, and they are expensive. Read more at https://www.mayoclinic.org/diseases-conditions/tinnitus/diagnosis-treatment/drc-20350162 https://www.drugs.com/condition/tinnitus.html

Hope this helps,

Gary