Yesterday, I found the lost chord.
I was revisiting a song I'd written with a friend about 30 years ago, with a view to re-recording it . I used to have a cassette with the recording on, but it somehow got lost during a house move.
It was the final chord in the chorus which allowed it to resolve comfortably.
Until yesterday, I hadn't been able to 'hear' that chord but finally, yesterday evening, I did.
By relaxing and letting go sufficiently, the 'lost chord' magically appeared again.
Now all I have to do is see if I can get away with singing it in as high a register as I did 30 years ago. ;)