I'm currently in the process of writing a song. I've got a tune and I'm putting the lyrics together but I'm always concerned that any tune I think of might just be another song I've heard somewhere randomly that I don't remember hearing.
Do I just have a shitty memory or is this a problem that other people have too?
When I come up with something particularly good, I take a screenshot of the melody + chord symbols and send it to a couple of my musician friends to ask if they recognize it as anything.
One time, they identified an idea as the bridge to an old pop song, but otherwise I've thankfully been in the clear.