I think you need more than just an answer in a topic like this in order to get a good understanding of your questions, but I can give you some idea as follows:
Regarding your first three questions:
What is a note?
What is a pitch?
How are pitch and note related?
Pitch is a particular frequency of a sound. When playing melodies you are playing sounds at different pitches.
The term note can have two meanings:
A) As a symbol: A note is a musical symbol which tells the duration of the pitch you are playing and when that symbol is placed in a musical staff it tells you which pitch to play.
B) As a sound: In this case a note is the name of the pitch you are playing. If you are playing an A you can say you are playing the note A, which means you are playing a sound that has that particular pitch named A.
And question number four:
- What is a scale? What is the difference between major and minor scale?
The term scale literally means ladder or stairs. A scale in music is a series of notes ordered in steps just like a ladder has steps, the notes are arranged by ascending or descending order of pitch. A musical scale has whole steps and half steps. The difference between major and minor scales is that the half steps are located at different places in the scales, like a major scale is a scale that starts with two whole steps while a minor scale is a scale that starts with a whole step followed by a half step. I think you better Google the subject in order to find out more about scales.