Leher saya kaku setelah duduk terlalu lama di depan komputer.

In Indonesian, possession is commonly shown by putting the owner after the noun.

• leher saya = my neck
• literally: neck I/my

This is very normal in Indonesian:

• rumah saya = my house
• nama saya = my name
• teman saya = my friend

So Leher saya is the natural way to say my neck.

You could also say leherku, which also means my neck, but leher saya is more neutral and common in careful standard speech.

Indonesian often does not use a verb meaning “to be” in simple sentences like this.

So:

• Leher saya kaku literally looks like My neck stiff
• but it naturally means My neck is stiff

This is completely normal. Indonesian usually leaves out is/am/are when describing something.

More examples:

• Saya lelah = I am tired
• Dia sakit = He/She is sick
• Rumah itu besar = That house is big

Kaku means stiff or rigid.

In this sentence, Leher saya kaku means your neck feels physically stiff, probably from posture or not moving for a long time.

It can also be used more broadly:

• physically stiff: Tangan saya kaku = My hand is stiff
• socially awkward or rigid: Dia kelihatan kaku = He/She looks stiff/awkward

But in this sentence, it clearly refers to physical stiffness.

Setelah means after.

In setelah duduk terlalu lama di depan komputer, it introduces what happened earlier:

• setelah = after
• duduk = sitting
• terlalu lama = too long / too long a time
• di depan komputer = in front of the computer

So the whole phrase means:

• after sitting too long in front of the computer

It connects the neck stiffness with the earlier action.

Because terlalu lama acts together to mean too long.

So:

• duduk terlalu lama = sit for too long / sitting too long

The adverb phrase terlalu lama modifies the duration of duduk.

This word order is natural in Indonesian:

• menunggu terlalu lama = wait too long
• bekerja terlalu lama = work too long
• tidur terlalu lama = sleep too long

Putting terlalu directly before duduk would sound wrong here, because terlalu is describing the length of time, not the action itself.

They are similar, but not the same.

• terlalu lama = too long
  
  • suggests excess, more than is good or comfortable
• lama sekali = very long / for a very long time
  
  • emphasizes length, but does not necessarily mean it was excessive

So in this sentence, terlalu lama is better because the idea is that sitting that long caused a problem.

Compare:

• Saya duduk terlalu lama. = I sat too long.
• Saya duduk lama sekali. = I sat for a very long time.

The second one does not automatically imply it was a bad idea.

Because di here is a preposition, meaning in / at / on depending on context.

When di is a preposition, it is written separately:

• di depan = in front of
• di rumah = at home
• di kantor = at the office

It is only written together with the following word when di- is a verb prefix:

• ditulis = written
• dibaca = read
• dibuka = opened

So:

• di depan komputer = correct
• didepan komputer = incorrect

Literally, di depan komputer means in front of the computer.

In natural English, depending on context, you might translate it as:

• in front of the computer
• at the computer

In this sentence, both give the same basic idea: you were sitting facing the computer for too long.

Indonesian often uses di depan in a very literal spatial sense, but in context it can overlap with English at.

Indonesian does not use articles like English a/an/the.

So:

• komputer can mean a computer, the computer, or just computer, depending on context

In this sentence, context tells us what is meant. English needs an article, but Indonesian does not.

Other examples:

• Saya beli buku = I bought a book / the book
• Dia masuk rumah = He/She entered the house

If Indonesian speakers want to be more specific, they use other words, not articles:

• komputer itu = that computer / the computer in context
• sebuah komputer = a computer

Yes. Leherku kaku is correct and means the same thing: My neck is stiff.

The difference is mostly style and register:

• leher saya = neutral, standard, a bit more formal
• leherku = more personal, closer, often used in casual speech or writing

Both are natural. In conversation, many speakers would use either depending on tone.

Similarly:

• rumah saya / rumahku = my house
• nama saya / namaku = my name

You could, but the meaning changes a little.

• setelah = after
• karena = because

Original:

• Leher saya kaku setelah duduk terlalu lama di depan komputer.
• My neck is stiff after sitting too long in front of the computer.

With karena:

• Leher saya kaku karena duduk terlalu lama di depan komputer.
• My neck is stiff because of sitting too long in front of the computer.

Both are possible, but:

• setelah focuses on the sequence in time
• karena focuses more directly on the cause

In everyday use, both can fit the situation.

Here, duduk is functioning as a verb: to sit / sitting.

After setelah, Indonesian often uses a verb directly without adding anything extra:

• setelah makan = after eating
• setelah pulang = after going home / after returning home
• setelah duduk terlalu lama = after sitting too long

Indonesian does not need a special -ing form like English does. The basic verb can often cover meanings like sit, to sit, or sitting, depending on context.

Yes, Indonesian allows some flexibility.

The original sentence:

• Leher saya kaku setelah duduk terlalu lama di depan komputer.

You could also say:

• Setelah duduk terlalu lama di depan komputer, leher saya kaku.

This puts the after... phrase first, which is also natural.

Both are correct. The difference is mostly emphasis:

• original order: starts with the main result (My neck is stiff)
• changed order: starts with the background/cause (After sitting too long...)

Yes, it is natural and correct.

A native speaker might also say similar versions such as:

• Leher saya terasa kaku setelah duduk terlalu lama di depan komputer.
  = My neck feels stiff after sitting too long in front of the computer.

• Leher saya pegal setelah terlalu lama duduk di depan komputer.
  = My neck feels sore/stiff after sitting too long in front of the computer.

• Leher saya sakit setelah duduk terlalu lama di depan komputer.
  = My neck hurts after sitting too long in front of the computer.

But your original sentence is perfectly good Indonesian.