Learn Hardcore Swedish: I dag har jag ont i huvudet, så jag tar en kort paus från datorn. - Today I have a headache, so I am taking a short break from the computer.

Traditionally, the “correct” spelling was i dag (two words).
Modern Swedish also accepts idag (one word), and that form is very common, especially in informal writing.

The same pattern exists with:

i går / igår – yesterday
i morgon / imorgon – tomorrow

In formal texts you still often see i dag, i morgon, i går, but in everyday writing idag, imorgon, igår are very common.

Could I also say “Jag har ont i huvudet i dag”? Is the word order “I dag har jag …” special?

Yes, you can say both:

I dag har jag ont i huvudet.
Jag har ont i huvudet i dag.

They are both grammatically correct and natural.

The difference is mainly emphasis:

I dag har jag ont i huvudet
– puts a bit more focus on “today” (today, as opposed to other days).
Jag har ont i huvudet i dag
– feels slightly more neutral; the time information comes at the end, like in English.

In Swedish it is very common to put time expressions first:

I dag, I morgon, På lördag
- verb + subject …
  This still follows the verb-second (V2) rule: after the first element (I dag), the verb (har) comes next.

What does the construction “har ont i …” literally mean, and how is it used?

Literally, har ont i … means “have pain in …”.

har = have
ont ≈ pain / ache
i = in

So Jag har ont i huvudet literally: “I have pain in the head.”

This is the normal way to talk about pain in a body part:

Jag har ont i ryggen. – My back hurts.
Hon har ont i magen. – She has a stomach ache / Her stomach hurts.
Han har ont i knät. – His knee hurts.

You cannot say “huvudet är ont” for “the head hurts” — that sounds wrong in Swedish. Use:

Jag har ont i huvudet.
Det gör ont i huvudet. – It hurts in my head.

Why is it “i huvudet” and not “på huvudet” or “mitt huvud”?

There are two points here: the preposition and the lack of a possessive.

Preposition: “i” vs “på”

i huvudet = inside the head (internal pain, headache)
- Jag har ont i huvudet. – My head hurts / I have a headache.
på huvudet = on the head (on the surface, e.g. scalp, skin)
- Jag har ont på huvudet. – It hurts on my head (e.g. a bump, cut or bruise on the outside).

So we say ont i huvudet for a typical headache.

No possessive: no “mitt”

Swedish usually omits possessive pronouns with body parts when it’s clear whose body part it is:

Jag tvättar händerna. – I wash my hands.
Han borstar tänderna. – He brushes his teeth.

Likewise:

Jag har ont i huvudet. – It’s understood that it’s my head.

Why is it huvudet with -et at the end? Why not just huvud?

Huvud is a neuter noun (ett huvud).

The forms are:

Indefinite singular: ett huvud – a head
Definite singular: huvudet – the head

In this sentence we say huvudet because Swedish uses the definite form of body parts when talking about one specific body part that belongs to the subject:

Jag har ont i huvudet. – literally “I have pain in the head (my head).”
Jag har ont i handen. – “My hand hurts.”
Jag har ont i ryggen. – “My back hurts.”

So huvudet is definite (“the head”), even though English does not show that.

Can I say “Jag har huvudvärk” instead of “Jag har ont i huvudet”? Are they the same?

Yes, you can say both, and in most contexts they mean practically the same:

Jag har ont i huvudet.
Jag har huvudvärk.

Both mean “I have a headache / My head hurts.”

Nuance:

huvudvärk is the noun “headache” and can feel slightly more medical or compact.
ont i huvudet is a very common everyday phrase and sounds a bit more descriptive.

In normal conversation, both are used a lot and are largely interchangeable.

What kind of word is ont here? Is it an adjective, a noun, or something else?

Historically, ont is the neuter form of the adjective ond (“bad, evil”), but in the expression ha ont (i …) it behaves like a fixed word meaning “pain” / “ache.”

You can think of ont here almost like a noun-like word:

ha ont i huvudet / magen / ryggen – have pain in the head / stomach / back

You don’t inflect it:

Not: har onda i huvudet – incorrect.
Always: har ont i …

So for learning purposes, it’s best to memorize ha ont (i + body part) as a set phrase.

Why is tar in the present tense? In English I might say “I’m going to take a short break.”

Swedish present tense is often used for actions that are:

happening right now, or
about to happen very soon.

So Jag tar en kort paus can mean:

“I’m taking a short break (now / right now).”

It’s similar to English present continuous (“I’m taking…”) or sometimes “I’ll take…” depending on context.

You can say:

Jag ska ta en kort paus. – I’m going to take a short break (plan/intention).
Jag kommer att ta en kort paus. – I will take a short break (more neutral prediction).

But in this sentence, tar works perfectly for something you’re doing now or immediately.

Why is there a comma before så, and what exactly does så mean here?

Here så means “so / therefore.” The two parts of the sentence are:

I dag har jag ont i huvudet,
så jag tar en kort paus från datorn.

The comma:

It separates two main clauses (two sentences that could stand alone).
In Swedish, it’s very common to put a comma before så when it means “so / therefore.”
- Det regnar, så vi stannar hemma. – It’s raining, so we’re staying at home.

So:

så here = “so / therefore”
The comma before så is stylistically normal and good to copy as a learner.

Why do we say “tar en kort paus” instead of “gör en kort paus” or “har en kort paus”?

Because Swedish has specific verb–noun combinations (collocations). With paus the usual verb is ta:

ta en paus – take a break
ta rast – take a break (at work)
ta semester – take vacation

So Jag tar en kort paus is the natural phrase.

Other options:

göra en paus – possible but uncommon and can sound more formal or stylistically marked.
ha paus – means “to be on break”:
- Vi har paus nu. – We’re on a break now.

For “I’ll take a short break,” stick with ta en paus.

Why is it från datorn (from the computer) and not just från dator?

Dator is a common gender noun:

en dator – a computer
datorn – the computer

We use datorn here because we mean a specific computer that is already known from context (the one you’re using now). In Swedish, when it’s clear which thing you mean, you normally use the definite form:

Jag sitter vid datorn. – I’m at the computer.
Jag tar en paus från datorn. – I’m taking a break from the computer.

Saying från dator (without the -n) is ungrammatical in standard Swedish in this context.

Could I say “en liten paus” instead of “en kort paus”? Is there a difference between kort and liten here?

Both are possible:

en kort paus – a short break
en liten paus – a little/small break

Nuance:

kort focuses on time / duration – not long.
liten focuses on size / degree, but with paus it often also implies short duration.

In practice, both commonly mean “a short break.”
En kort paus is a bit more neutral and precise about time; en liten paus can sound a bit softer or more colloquial, sometimes with a hint of modesty or understatement.