What is the difference between aptitude and Intuition?
If one has aptitude for a certain activity, it means that learning that activity is easy- your mind readily absorbs and retains those learnings, and you master that activity quickly and easily.
Intuition is the unconscious accessing or remembering of past experience which provides a path forward to the solution of some problem in the present. For example, a musician will "intuit" the next musical chord in an unfamiliar progression and play it correctly the first time- either by remembering a similar progression (s)he learned in the past, or by knowing (through learning or experience) the structure of the melodic movement behind the progression well enough to anticipate where the progression is leading.
In any case, the musician does not have to stop playing, ask for a piece of sheet music with the part written out on it, or walk over to a piano and play through the progression to that point in order to deduce the next change.