Is this external or internal conflict? John's in the cold as he fished through his coat pocket for a match. He had already gathered scraps of wood and piled them to make a fire. Now he had to figure out how to kindle it.

It is an external conflict.

Conflicts are the situations that advance the plot of a story. Fundamental to entertain the reader, because through them the characters express themselves. The external conflict is one that occurs between two or more characters or a character and their environment.

In the fragment, the conflict is between the main character and his environment, which is very cold and uncomfortable. The character should learn how to make the fire to face the adverse situation.