Portugal had difficulty colonizing because they: did not have ships to take people to the colonies were not interested in colonizing lacked resources, population, and size

were not interested in colonizing

Explanation:

At first, the Portugal were not interested in colonizing the world. The other European countries like Britain, French, Germany, etc. started exploring other lands in search of food and doing trade business. They occupied parts of Asia and also America with the intention of doing trade and later on started controlling and declared wars on the native places of the people.

Finally they colonized various parts of the world and stared exploiting the resources in their interest. Thus at first Portugal did not had any intention to capture any land but they did so to prevent other European countries to declare and claim their territories in which they are doing business.