Answer:
QUESTION1: What chain of events leads the boy to work at the crystal shop?
ANSWER : He was robbed by a thief, which made him loss all his flock of sheep as a shepherd he was before. He needed to have a job, so as to save up money, and buy a new flock of sheep, to restart his business.
QUESTION2: What does he learn there?
ANSWER: Santiago learnt that a much greater goal exist, than just pursing a comfortable life style. That is why he continued in pursuit of his personal legend, which was the trip across the desert to the pyramid in Egypt, instead of going back home to continue his comfort life style of being a shepherd.
QUESTION3: Why (not how) is he able to change and improve the shop, which has remained the same for many years?
ANSWER: Santiago was able to change the shop that has been the same for years, because he was ambitious, and also has foresight. He was always willing to try new things and expand his tentacles.
QUESTION4: How is he different from the shop's owner?
ANSWER: Santiago is different from the crystal shop owner, because he was will to conquer his fears and achieve his dreams, while the crystal shop owner was afraid of not having anything to leave for, if he achieve his dreams of going to Mecca.
Another differents was that Santiago always wants to take the risk and try a new thing to achieve higher, while the shop owner, is always afraid of taking a risk.