Can't re-upload song to my iPhone

I wanted to add lyrics to a song already on my phone (an uploaded file, not one from iTunes Store). Since one can't edit a song directly on the iPhone, I deleted it (removed from library - which was the only option offered), added the lyrics to the file on my Mac and tried to re-upload it to my phone by dragging the file from Finder to the iPhone icon on the left-hand bar, or by right clicking and selecting Add to Device.

Nothing happens. I have not been able to re-upload the song.

The file was not deleted on my computer (I can see it using Finder), so I know it is still there.

Why won't Music upload it to my phone?

I am using Music 1.5.2.56.