simply copying a section of your own silence from the waveform and Pasting it in?
That would be yes.
That's not "silence," that's Room Tone. If you don't have enough Room Tone, you'll have to make it by repeatedly pasting what you've got.
The more you're not recording in a studio, the more matching Room Tone is difficult. If you're not even pretending to record in a studio, then you'll need to match cars and trucks, dogs, air conditioning, etc.
By the way, this just kills you if you're trying to record an interview in the field for later editing. If there's music in the background that can destroy the interview.