wehtun
to hurt
To cause or feel physical pain.
Vorsicht, der Topf ist heiß und tut weh, wenn du ihn anfasst!
Careful, the pot is hot and hurts if you touch it!

to hurt
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to hurt
To cause or feel physical pain.
Vorsicht, der Topf ist heiß und tut weh, wenn du ihn anfasst!
Careful, the pot is hot and hurts if you touch it!

'Wehtun' (to hurt) is a separable verb. The prefix 'weh' comes at the end of the main clause. In the infinitive with 'zu', it is written as 'weh zu tun'.
Mein Kopf tut schon den ganzen Tag weh.
My head has been hurting all day.
The person who feels the pain is always in the dative. The thing that causes the pain (e.g., a body part or an action) is the subject of the sentence.
Der Zahn tut mir weh.
My tooth hurts.
The context makes it clear whether physical or emotional pain is meant. Body parts like 'Arm' (arm) or 'Bauch' (belly/stomach) point to physical pain, while abstract nouns like 'Kritik' (criticism) or 'Trennung' (separation/breakup) point to emotional pain.
Nach dem langen Lauf tun meine Beine weh.
After the long run, my legs hurt.
The reflexive form 'sich wehtun' (to hurt oneself) means to injure oneself. The reflexive pronoun is in the accusative. If you name the injured body part, the pronoun is in the dative and the body part is in the accusative.
Das Kind ist hingefallen und hat sich wehgetan.
The child fell down and hurt themselves.
to meet / to hit
'treffen' and 'wehtun' can both express that something is painful for someone. 'wehtun' names the pain directly: physical, for example in the knee, or emotional, for example because of harsh words. 'treffen' describes more the effect on a person: a statement, criticism, or event affects someone strongly or hurts them inside. Learners may confuse the words because both can fit when talking about feelings. If you mean the pain itself, 'wehtun' is more natural. If you want to say that something reaches someone emotionally in a strong way, 'treffen' works well.

Clara tut der Fuß weh, weil sie am Wochenende lange gewandert ist.
Clara's foot hurts because she went on a long hike at the weekend.
Seine Kritik hat sie sehr getroffen, obwohl er ruhig gesprochen hat.
His criticism hurt her deeply, even though he spoke calmly.