I have asked this question from my intro to music college professor, many years ago, and his answer was in the negative. I have searched the internet for answers but not found any.
There are many similar sounding tunes out there, especially in pop music and many people have been sued for copyright violations. So there are similarities.
A recognizable musical tune can be hummed or played on a single instrument. A composer can choose the notes as well as the timing and sequence in which they played. A popular tune can be recognized if someone hums the tune of the first verse. A composer has to avoid duplicating any previous tune.
There must be a theoretical limit to the number of note sequences that can be constructed out of a set of notes. Isn't it reasonable to assume, and possible to calculate, the total number of recognizable melodies that can be created from these? Doesn't it limit the number of songs that can ever be written?
To put things in perspective, though, no one has ever heard all the songs ever composed in all cultures since the beginning of time, so there maybe exact duplicates of song melodies but without anyone knowing.