The verb “doler” means to feel pain, when speaking of a part of the body. It is irregular because it is a stem changing verb. The letter o in the infinitive form changes in ue when conjugated in some tenses:

D O LER – D UE LE.

Note that by definition, this verb is strictly linked to a part of the body. The part that hurts is the subject of a sentence with the verb doler. And because what hurts is la cabeza or los pies (and not yo, tú, or ella,), the right thing to do is to conjugate it in the third person: singular (me duele la cabeza) or plural (me duelen los pies).

Then we must specify the person who is feeling the pain which is the recipient of that action; that is why we refer to that person (or people) with an Indirect Object Pronoun (me, te, le, nos, os or les).

These pronouns will be placed before the conjugated verb:

¿Te duele la espalda?

If the verb is in the infinitive or gerund form it can be placed before the verbal construction or right after it:

- Doctor, a la paciente continúa doliéndole la mano.

- Enfermera, ¿me va a doler la inyección?

Finally, if we add the Indirect Object to the sentece (i.e. the name of the person who feels the pain or a pronoun that refers to that person) then the preposition a introducing the receiver must be included:

- A ella le duelen los oídos.

- A los niños les duele el estómago