Pani w gabinecie mówi, że szczepienie trwa krótko, a zastrzyk zwykle nie boli długo.

Here pani means lady / woman / female professional, depending on context.

In a medical sentence like this, pani w gabinecie most naturally means something like the woman in the office/exam room, often understood as a nurse, doctor, or receptionist.

It is also the standard polite word for Mrs./Ms./ma’am in Polish, but in this sentence it is being used as a noun, not as direct address.

Because here it is just an ordinary noun in the sentence.

• pani = the lady / the woman
• Pani = often used as a polite form of you in writing, or when directly addressing someone respectfully

So:

• Pani mówi, że... can mean You say that... in a polite letter or formal message.
• Pani w gabinecie mówi, że... means The lady in the office says that...

In your sentence, it is clearly the second use, so lowercase pani is normal.

Because w meaning in takes the locative case when it shows location.

The basic form is:

• gabinet = office / consulting room / study

After w for location, it changes to the locative:

• w gabinecie = in the office / in the consulting room

So this is a case ending issue:

• nominative: gabinet
• locative: w gabinecie

In medical context, gabinet usually means doctor’s office, consulting room, exam room, or treatment room.

It does not mean a large government cabinet here, and it also does not mean a piece of furniture.

So pani w gabinecie is best understood as someone working in the medical room or office.

Że means that.

After verbs like mówi (says), Polish often uses że to introduce what someone says:

• mówi, że... = says that...

So:

• Pani w gabinecie mówi, że szczepienie trwa krótko...
• The woman in the office says that the vaccination takes a short time...

Also, Polish normally puts a comma before że, so mówi, że is exactly what you should expect.

Because trwać means to last, and krótko is an adverb meaning briefly / for a short time.

So:

• szczepienie trwa krótko = the vaccination lasts a short time / does not take long

If you said:

• szczepienie jest krótkie

that would mean the vaccination is short, which is understandable, but less natural in this context. Polish often prefers trwać + krótko/długo when talking about duration.

A useful contrast is:

• krótki = short, as an adjective
• krótko = shortly / briefly, as an adverb

Here you need the adverb, because it describes how long the action lasts.

They are related, but not identical.

• szczepienie = vaccination
• zastrzyk = injection / shot

A vaccination can be given by an injection, so the two ideas are connected. But the words focus on different things:

• szczepienie focuses on the medical procedure or immunization
• zastrzyk focuses on the physical injection itself, the jab

So the sentence first talks about the whole event:

• szczepienie trwa krótko = the vaccination is quick

Then it talks about the painful part people worry about:

• zastrzyk zwykle nie boli długo = the shot usually does not hurt for long

In Polish, boleć means to hurt / to ache / to be painful.

It is very normal to make the thing causing pain the grammatical subject:

• zastrzyk boli = the injection hurts
• to boli = that hurts

So zastrzyk zwykle nie boli długo literally looks like:

• the injection usually does not hurt long

Natural English would be:

• the injection usually does not hurt for long
• or the shot is not usually painful for long

Polish often uses this structure very naturally, even where English might prefer a different wording.

A often links two statements that are connected but slightly contrasted or balanced.

Here the sentence has two related parts:

• szczepienie trwa krótko
• zastrzyk zwykle nie boli długo

Using a gives a feeling like:

• and / while / and also
• with a slight sense of here is another related point

So it sounds like:

• The vaccination is quick, and the injection usually doesn’t hurt for long either.

If you used i, it would simply mean and. That is possible in some contexts, but a sounds very natural here because it neatly connects two separate reassuring facts.

Because the sentence expresses a general statement, not a one-time event happening right now.

Polish uses the present tense for things that are generally true or usually true:

• szczepienie trwa krótko = a vaccination takes a short time
• zastrzyk zwykle nie boli długo = an injection usually does not hurt for long

This is like English present tense in general statements:

• Water boils at 100°C
• Vaccinations are quick

So the present tense here is not about one specific injection only. It is about what is usually the case.

Because Polish has no articles like English a/an/the.

So a word like pani can mean:

• a woman
• the woman
• the lady

and the exact meaning depends on context.

The same is true for:

• gabinet = an office / the office
• szczepienie = a vaccination / the vaccination
• zastrzyk = an injection / the injection

English speakers often look for articles in Polish, but Polish simply does not use them. You understand definiteness from the situation, word order, and context.

Yes, it is natural.

Here długo means for a long time / long and it modifies boli:

• nie boli długo = doesn’t hurt for long

That is a normal and clear order in Polish.

You could move words around for emphasis, because Polish word order is more flexible than English, but this version is neutral and natural:

• zastrzyk zwykle nie boli długo

It is also useful to notice the parallel with the first half:

• trwa krótko
• nie boli długo

Both use adverbs of duration:

• krótko = briefly / for a short time
• długo = long / for a long time

Not always. In this sentence they are best understood as duration words.

• krótko here = for a short time / briefly
• długo here = for a long time / long

So:

• trwa krótko = lasts a short time
• nie boli długo = doesn’t hurt for long

A very literal word-for-word translation can sound strange in English, so it is better to translate the whole phrase naturally rather than each word separately.