Learn Hardcore Korean: mogi apayo.

It can mean either, depending on context. In everyday health talk, 목이 아파요 is most often understood as “My throat is sore.” If you specifically mean muscle/neck pain, you can say:

For a stiff/sore neck: 목이 결려요, 목이 뻐근해요
For the back of the neck: 뒷목이 아파요
For the nape: 목덜미가 아파요

Why is there 이 after 목?

이 is the subject marker. It marks 목 (neck/throat) as the grammatical subject of the sentence. Use 이 after a noun ending in a consonant (like 목), and 가 after a noun ending in a vowel. So:

목이 아파요 = My throat/neck hurts.
If the noun ended in a vowel: 배가 아파요 (My stomach hurts).

What’s the difference between 이/가 and 은/는 here?

목이 아파요 simply states the fact that the throat/neck hurts (neutral/new information).
목은 아파요 contrasts or topicalizes: “As for my throat/neck, it hurts (but maybe other parts don’t).” Use 이/가 for neutral focus; 은/는 for contrast or topic-setting.

Can I drop the particle and say 목 아파요?

Yes, in casual speech Koreans often drop particles. 목 아파요 is natural in conversation. In careful or formal speech, keep 이: 목이 아파요.

Where is “my”? Why isn’t it 제?

Korean typically omits possessives for body parts when it’s obvious whose body part it is. 목이 아파요 is understood as “My throat hurts.” Use 제 목이 아파요 only to emphasize or clarify ownership (e.g., contrasting with someone else’s).

Should I ever say 목을 아파요?

No. 아프다 is intransitive: the painful thing is the subject, not the object. Say 목이 아파요, not 목을 아파요. Use 목을 다쳤어요 (“I injured my neck”) for “hurt” in the sense of injure.

How is 아파요 formed from 아프다?

아프다 is a ㅡ-irregular verb. When adding -아/어, drop the ㅡ and choose -아 if the preceding vowel is ㅏ or ㅗ, otherwise -어. In 아프다, the preceding vowel is ㅏ, so:

아프다 → 아파요 (present polite)
Past: 아팠어요
Future/probable: 아플 거예요
Casual: 아파
Formal: 아픕니다
Connective: 아파서 (because [it] hurts)

How do you pronounce 목이 아파요? It sounds like “mogi apayo.”

Correct. Liaison makes 목이 sound like 모기 [mo-gi]. So 목이 아파요 is pronounced roughly [모기 아파요]. Don’t confuse it with 모기 (“mosquito”); context makes the meaning clear.

Is 아퍼요 ever correct?

Standard spelling is 아파요. You may hear people pronounce it a bit like 아퍼요, but write 아파요.

How polite is 아파요? What are other levels?

아파요 is polite informal (default for most situations). Other options:

Casual: 아파
Honorific (to/ about someone you respect): 아프세요? / 아프세요.
Formal: 아픕니다 / 아픕니까?

How do I ask someone “Does your throat hurt?”

Neutral polite: 목이 아파요?
Honorific (to elders/patients): 목이 아프세요?
Casual: 목 아파?

How can I be more specific about the feeling (scratchy, stinging, etc.)?

Scratchy/dry: 목이 칼칼해요, 목이 따가워요
Hoarse voice: 목이 쉬었어요
Swollen: 목이 부었어요
Stiff/aching neck: 목이 결려요, 목이 뻐근해요

How do I make it stronger or softer?

Add adverbs:

Softer: 조금/좀 목이 아파요 (It hurts a little)
Stronger: 많이 목이 아파요 (It hurts a lot), 너무 목이 아파요 (It hurts so/too much)

Can 아프다 also mean “to be sick,” not just “to hurt”?

Yes. With a person as the subject, 아프다 often means “to be ill.” For example, 저 아파요 can mean “I’m sick (not feeling well).” With a body part as the subject (like 목이), it means that part hurts.

Is the sentence a statement or a question? It looks the same.

It’s a statement if said with falling intonation: 목이 아파요. To ask a question, raise your intonation and/or use a question mark: 목이 아파요? Context and tone distinguish them.