When you come up with a melody either for the vocals or the guitar, do you guys sometimes subconsciously take an existing song that you've heard long time ago, and think that you came up with the melody originally?

Right now Im trying to come up with melodies that i can incorporate into a song, but Im afraid i might be actually taking something very similar in nature of other songs that I've heard.
There are so many songs that this is bound to happen at least a little bit, but I'm afraid this is probably in the wrong forum...
ok, yeah. my name is silly because I signed up when I was 13.

Yah, it's kind of difficult to come up with something completely original. It can be done though.