Learn Dutch: De enkel en de teen doen pijn. - The ankle and the toe hurt.

In Dutch, it is very common to use definite articles (de or het) instead of possessive pronouns for body parts. This is especially true when it is obvious whose body part is affected, or when describing general symptoms.

How would I specify that they hurt me using the grammar from this lesson?

You would add the object pronoun mij (or me) to indicate who is experiencing the pain: De enkel en de teen doen mij pijn. This uses the object pronoun to show possession, meaning you still keep the definite articles instead of changing them to mijn.

How does the grammar of pijn doen work in this sentence?

The expression pijn doen literally means "to do pain." The body parts causing the pain act as the subject of the sentence. Because there are two body parts here (de enkel en de teen), the subject is plural, so we use the plural verb doen instead of the singular doet.

I have seen enkel used to mean "single" or "a few." Is this related?

They are spelled the same but have different meanings based on the context. As a noun, de enkel means "the ankle." As an adjective or pronoun, enkel (often enkele) means "single," "only," or "a few."