Question about Guitar Harmonics?

No. A pinch harmonic is a slang term for an artificial harmonic. These are produced when the thumb of the picking hand strikes the string immediately after the pick does. You can create a natural harmonic by lightly tapping a note exactly 12 frets higher than any given note. You can create a "pinch" harmonic at almost any point along the distance of a string by moving the point that you pick the note and "dig in" with the thumb up and down the length of the string. Certain points will ring out with more clarity than others, depending on the strength of the harmonic "node".