A note on a guitar, is simply a fretted string plucked.  At first, playing notes can hurt both hands. Most players use a plectrum to pluck.

<----- plectrums.

However, guitarists eventually get used to the slight pain.

Basic playing techniques. 

Bending-when the fret hand is used to bend the string up and down.  Tab abbreviation-b

Sliding-when the next note is reached by sliding down the fret board without lifting your hand. Tab abbreviation-/

Hammer on-when the next note is slammed by the finger without plucking the string. Tab abbreviation-h

Try the intro to Radioheads airbag, which uses all 3 of these techniques.