The influence of songs ya heard is a real thing, at least for me. I have often wondered and then asked people if a new melody is 'stolen' from somewhere. I can't remember what I ate for breakfast or what colour my undershorts are, but some tune I heard once when I was tey years old will pop into my head and what's THAT about.

One of the very first songs I ever wrote waaaaaay back had a great melody. GREAT. Catchy as all get out. Unfortunately it was the opening descending run for the song "Surfing Safari", and that was pointed out to me by a musical friend. It was then I realized the kids from California had wonderful talent. -:)

To get the creative stuff flowing I often park it and diddle with chord progressions. Part way through a set of chording runs I'll try things--wonder what happens when ya do THIS kinda thing--and if something about it sounds new or 'works', I'll put time in it and strart looking for words. Sometimes some words come first and I go looking for backup. Confucing to explain, but songwriters will know what I mean.