Pretty constantly most of my life, and just for added annoyance, about a year ago it progressed to where I sometime hear two different pitches out of my ears - so one ear hears everything about a quarter tone higher/lower than the other ear. It makes everything sound like I’m in a tin can, and music becomes unbearable while it is going on. Fortunately, it so far only lasts maybe an hour or so at a time. We’re pretty sure it is allergy related for me. My doctor had me double up my allergy meds and add Flonase to try to keep fluid off my ears. It helps if I keep ahead of it. So long as it doesn’t start happening while I’m trying to sing, I’m okay, but there is no way I could sing while it is going on. I honestly can’t tell which pitch is the correct pitch - really frustrating for a musician.