French does not say "my head hurts". It says you have pain at the body part: avoir mal à + the definite article. Remember the contraction: à + le = au, à + les = aux, while à la and à l' stay as they are.
Examples
- J'ai mal à la tête.
- I have a headache.
- Il a mal au dos.
- His back hurts.
- Elle a mal aux dents.
- Her teeth hurt.
The mistake to avoid
Use the definite article, not a possessive: "j'ai mal à ma tête" is not natural French.
Where this fits in
Body, health & feelings, French A2: Talk about your body, common illnesses, and how you feel. Visit a doctor or pharmacy and describe symptoms.