I'll quote Dave (and wikipedia)
"The lyrics to this song follow a series of different themes, as Grohl noted himself, "Oh, my God, that song's about 15 different things! The only reason why it's called 'Hey, Johnny Park!' is because when I was young, my best friend was this kid who lived across the street from me called Johnny Park and we were like brothers from the age of 5 to 12. I haven't heard from him since I was about 14 years old and I thought if I named a song after him he might call."[5] It is notable as being a rare example of a Foo Fighters song featuring synthesisers."
I hope that answers your questions.
I'll quote Dave (and wikipedia) "The lyrics to this song follow a series of different themes, as Grohl noted himself, "Oh, my God, that song's about 15 different things! The only reason why it's called 'Hey, Johnny Park!' is because when I was young, my best friend was this kid who lived across the street from me called Johnny Park and we were like brothers from the age of 5 to 12. I haven't heard from him since I was about 14 years old and I thought if I named a song after him he might call."[5] It is notable as being a rare example of a Foo Fighters song featuring synthesisers." I hope that answers your questions.