Head voice/chest voice refers to where the voice resonates, not how the sound is produced. Falsetto has to do with how the sound is produced.

Basically (to paraphrase what has been said before), as the pitch rises, the place that it resonates moves from your chest up toward your teeth--that's the chest to head voice business.

The differences that you're talking about are called breathy voice(or soft voice), normal voice, and hard voice, and have to do with the volume of the voice, rather than the pitch. Singing is normally done in hard voice. Soft voice singing is kind of a novelty that some performers use as kind of a signature--and it comes and goes--but it has been used a lot by folk types, even male type singers--remember "Greenfields", or Donovan?

Pop recordings favor the use of vocal gimmicks of one sort or another, often high pitched ones, because they appeal to kids, who pretty much are the market for pop music.