I had no response from this forum on my question and today I found the answer and want to share with the community as I suspect anyone who became a Yosemite user may have this situation:
Today I went to the Apple store in Lancaster PA because my iPhone4 which has a 32GB memory was showing near full and I had discovered that there was music amounting to 10.6GB that was “hidden” from iTunes and could not be deleted. It remained when I discontinued synching the music. The music was loaded once upon a time by me, but for some reason, I suspect Yosemite was involved since in January I converted my iMac to the Yosemite OS. Under Snow leopard my play lists on the phone were sometimes different than on my desktop (on purpose) and Yosemite does not permit playlists with the same name to be different on devices. So I think the phone ‘saved” the old without my knowing when I synched after changing to Yosemite. The music I have loaded would remove, but not the “hidden”.
One trick I had tried was to change the date in the phone to a date about five years ago. But unlike with "hidden" deleted photos, the music did not appear in iTunes. At the Apple store the answer was to go on the iPhone to Settings, General, usage, and look for the music app icon. Select and choose to delete and that deletes all music off the phone, and frees up the space. The delete action is not instantaneous, it took maybe five minutes. Then coming home I could re-synch and return all my favorite songs and audio lessons. Now instead of having 5GB free, I have almost 18GB free with the music I want on it and am able to manage. Yea !!!!
And maybe that solution would have worked for the "deleted" photo situation many had elsewhere in this discussion group and saved the trouble of changing the date. Always something new to learn!