Vrat me boli kad dugo sjedim u uredu.

Croatian uses the verb boljeti differently from English.

In this pattern, the thing that hurts is the grammatical subject, and the person who feels the pain is expressed with a pronoun like me.

So Vrat me boli is literally closer to The neck hurts me, but it naturally means My neck hurts.

Saying Moj vrat boli by itself sounds incomplete or unnatural in this sense. The usual pattern is:

• Glava me boli = My head hurts
• Leđa me bole = My back hurts
• Vrat me boli = My neck hurts

Vrat is in the nominative singular here, because it is the subject of boli.

That can be confusing for English speakers because the meaning feels like my neck is the thing being affected, but grammatically in Croatian it is the thing that does the hurting.

So:

• vrat = nominative subject
• me = the person affected

Also, vrat is a masculine noun, and in the singular its nominative form is just vrat.

Me is the unstressed accusative form of ja.

Here it means me, as in it hurts me.

So the structure is:

• vrat = neck
• me = me
• boli = hurts

Together: The neck hurts me → natural English: My neck hurts

This is a very common Croatian pattern with pain and discomfort.

Croatian often leaves possession unstated when it is obvious, especially with body parts.

So Vrat me boli normally already means my neck hurts, not just the neck hurts me in some random sense.

If you add moj, it gives extra emphasis or contrast:

• Moj vrat me boli, a leđa ne. = My neck hurts, but my back doesn’t.

But in an ordinary sentence, moj is usually unnecessary.

Because vrat is singular.

The verb agrees with the subject:

• Vrat me boli. = My neck hurts.
• Leđa me bole. = My back hurts.
• Oči me bole. = My eyes hurt.

So:

• singular subject → boli
• plural subject → bole

Yes. In fact, Boli me vrat kad dugo sjedim u uredu is probably the more neutral word order.

The version Vrat me boli... puts more focus on vrat, as if you are highlighting the neck specifically.

Croatian word order is flexible, but the meaning stays the same here.

So both are correct:

• Boli me vrat kad dugo sjedim u uredu.
• Vrat me boli kad dugo sjedim u uredu.

The second one sounds a bit more emphatic on neck.

Because me is a clitic: a short, unstressed word that usually goes near the beginning of the clause, often in second position.

That is why Croatian tends to place pronouns like me, te, ga, joj, mi very early.

So:

• Vrat me boli sounds natural
• Vrat boli me does not

This is a very important Croatian word-order habit.

Kad means when, and in sentences like this it can also have the sense of whenever.

Here the meaning is general/habitual:

• Vrat me boli kad dugo sjedim u uredu.
• My neck hurts when/whenever I sit in the office for a long time.

Also, kad is the shorter everyday form of kada. Both are correct:

• kad dugo sjedim
• kada dugo sjedim

Because sjedim comes from the imperfective verb sjediti, which describes an ongoing state: to sit / to be sitting.

That fits dugo very well:

• dugo sjedim = I sit for a long time / I am sitting for a long time

By contrast, sjednem comes from sjesti, which means to sit down once, the action of taking a seat.

So:

• sjedim = I am sitting / I sit
• sjednem = I sit down

In this sentence, the pain happens during prolonged sitting, so sjedim is the right choice.

Here u means in, and because it expresses location, it takes the locative case.

The noun is:

• ured = office
• uredu = in the office

So:

• u uredu = in the office

This contrasts with movement:

• u ured = into the office

So the sentence uses u uredu because it describes where you are sitting, not movement into that place.

Sometimes yes, but the nuance changes a little.

• kad = when / whenever
• dok = while

In your sentence, kad is very natural because it describes a repeated situation or trigger: when I sit for a long time in the office

If you say dok dugo sjedim u uredu, it sounds more like while I am sitting in the office for a long time.

So dok is possible in some contexts, but kad is the more straightforward choice here.

Because Croatian often drops subject pronouns when the verb already shows who the subject is.

The form sjedim already means I sit / I am sitting, so ja is not necessary.

You could say kad ja dugo sjedim u uredu, but that would add emphasis, something like:

• when I am the one sitting for a long time in the office

Normally, the natural version is simply:

• kad dugo sjedim u uredu