*20 points*
why did so many african countries face difficult challenges after winning their independence?

The African countries lacked infrastructure and other technologies which were responsible for challenges in the African countries.

Explanation:

Even after getting independence, the African countries could not see much growth and development even though these countries were geographically rich in minerals and resources.

Because there were not much infrastructure available for the growth and development and moreover there was not much technology available for the development which could increase the productivity of those countries for increasing the goods manufactured and develop the economy by increasing the efficiency or effectiveness of the countries.