Lưng của tôi đang đau.

A natural word-by-word breakdown is:

• lưng = back
• của tôi = my / of mine
• đang = currently, in the process of
• đau = hurt, painful, ache

So the structure is roughly:

Back of mine currently hurts
or more naturally in English: My back hurts / My back is hurting.

Because lưng is the thing that hurts, and của tôi shows possession: my back.

So:

• lưng = back
• lưng của tôi = my back

Vietnamese often marks possession with của:

• nhà của tôi = my house
• sách của tôi = my book
• lưng của tôi = my back

That said, in everyday Vietnamese, people often use the shorter form lưng tôi, which also means my back.

Yes. Lưng tôi đang đau is completely natural and often more conversational.

Both mean the same thing:

• lưng của tôi đang đau
• lưng tôi đang đau

The version with của can sound a little more explicit or slightly heavier. In daily speech, Vietnamese often drops của when the relationship is obvious.

Đang shows that something is happening right now or is currently in progress.

So:

• Lưng của tôi đau = My back hurts
• Lưng của tôi đang đau = My back is hurting right now / currently

In many situations, Vietnamese does not need đang if the time is already understood. So đang adds a stronger sense of at the moment.

No, it is not required.

You can say:

• Lưng tôi đau. = My back hurts.
• Lưng tôi đang đau. = My back is hurting right now.

The second one emphasizes the present ongoing condition more clearly. The first is also very natural and common.

Because Vietnamese often does not use a verb like English to be in this kind of sentence.

English says:

• My back is painful
• My back is hurting

Vietnamese can simply say:

• Lưng tôi đau

Here, đau works like hurt / painful, and no separate is is needed.

This is very common in Vietnamese grammar.

It behaves somewhat like both, depending on how you look at it.

In learner-friendly terms, it is best to think of đau as meaning to hurt / painful / sore.

Examples:

• Tôi đau đầu. = I have a headache / My head hurts.
• Tay tôi đau. = My arm hurts.
• Lưng tôi đau. = My back hurts.

So in real usage, you do not need to worry too much about forcing it into one English category. Just learn that đau is the normal word for physical pain or hurting.

It is correct, but in everyday speech many speakers would more naturally say:

• Tôi đau lưng.
• Lưng tôi đau.

Both are very common.

A very useful pattern in Vietnamese is:

• Tôi đau + body part

For example:

• Tôi đau đầu. = My head hurts / I have a headache.
• Tôi đau bụng. = My stomach hurts.
• Tôi đau lưng. = My back hurts.

So while Lưng của tôi đang đau is understandable and correct, Tôi đau lưng is often the most common everyday phrasing.

Both usually mean My back hurts, but they focus slightly differently.

• Lưng tôi đau puts the body part first: My back hurts
• Tôi đau lưng puts the person first: I have back pain / My back hurts

In normal conversation, the difference is small.
Tôi đau lưng is especially common as a standard way to talk about body pain.

You can use that as a grammar aid, but not as a natural English translation.

A literal-style breakdown is:

• lưng của tôi = the back of me / my back
• đang đau = is hurting

But in real English, you would simply say:

• My back hurts
• My back is hurting

Literal translations can help you understand structure, but they should not always be copied into natural English.

Because Vietnamese possession often works in the order:

noun + của + possessor

So:

• lưng của tôi = back of me = my back
• xe của anh ấy = car of him = his car
• nhà của cô ấy = house of her = her house

English puts the possessor first, but Vietnamese often puts the thing first.

Also remember that Vietnamese can shorten this:

• lưng tôi
• xe anh ấy
• nhà cô ấy

A few important points:

• lưng has the ưng sound, which may be tricky for English speakers.
• của and tôi should be pronounced clearly and separately.
• đau sounds roughly like dow in English, but with Vietnamese pronunciation.
• đang has the ang vowel and must not be confused with similar-looking words.

Tones matter too:

• tôi
• đang
• đau

If you say the wrong tone, people may still guess your meaning from context, but it is good to practice them carefully from the beginning.

Yes. Tôi is just the pronoun I / me, and Vietnamese pronouns change depending on age, relationship, and situation.

For example:

• Lưng em đang đau. = My back hurts.
• Lưng anh đang đau. = My back hurts.
• Lưng con đang đau. = My back hurts.

The grammar stays the same; only the pronoun changes.
So in real life, the most natural pronoun may not be tôi.

A very natural everyday choice is:

• Tôi đau lưng.

Also common:

• Lưng tôi đau.
• Lưng tôi đang đau.

So if your goal is practical spoken Vietnamese, Tôi đau lưng is probably the best sentence to remember first, while Lưng của tôi đang đau is useful for understanding grammar and sentence structure.