Po pracy szybko się męczę, więc wieczorem wolę zostać w domu.

Because the preposition po here means after, and in this use it requires the locative case.

• nominative: praca = work
• locative: pracy

So:

• po pracy = after work

This is a very common expression in Polish.

The base verb męczyć usually means to tire, to exhaust, or sometimes to bother/annoy someone.

With się, it becomes męczyć się, which means to get tired, to tire oneself, or sometimes to struggle.

In this sentence:

• męczę się = I get tired

So Po pracy szybko się męczę means After work, I get tired quickly.

Also, męczę is the 1st person singular present tense form: I get tired / I am getting tired.

Się is part of the reflexive form of the verb: męczyć się.

Without się:

• męczyć kogoś = to tire someone

With się:

• męczyć się = to get tired

So the sentence is not saying I tire someone quickly. It is saying I get tired quickly.

For many Polish verbs, the meaning changes a lot when się is added, so it is best to learn męczyć się as a whole expression.

Polish word order is more flexible than English word order, but some orders sound more natural than others.

Szybko się męczę is a very natural neutral order.

Here:

• szybko = quickly
• się męczę = I get tired

You could also hear:

• Męczę się szybko

That is also correct, but it shifts the emphasis a little.

What is less natural is splitting things in a clumsy way, for example:

• szybko męczę się

That sounds awkward in normal speech.

A useful rule: się usually does not go at the very beginning of a sentence, and it often appears close to the verb.

Literally, szybko means quickly.

So:

• szybko się męczę = I get tired quickly

But in natural English, this can overlap with I tire easily, depending on context. The Polish sentence mainly focuses on speed: after work, tiredness comes fast.

Więc means so, therefore, or thus.

It connects the two ideas:

• Po pracy szybko się męczę = After work I get tired quickly
• więc = so
• wieczorem wolę zostać w domu = in the evening I prefer to stay at home

So więc introduces the result or consequence.

Wieczorem is a very common adverbial time expression meaning in the evening.

It comes from wieczór and uses the instrumental case in an adverb-like way, just like some other time expressions in Polish:

• rano = in the morning
• wieczorem = in the evening
• nocą = at night
• latem = in summer

So:

• wieczorem = in the evening

Using w wieczór would usually not sound natural here.

Because zostać w domu means to stay at home, especially in the sense of not going out.

That fits the idea of a decision or preference very well:

• wolę zostać w domu = I prefer to stay at home

If you say:

• wolę być w domu

that means more literally I prefer to be at home. It is grammatically possible, but it does not express the same idea as naturally. Zostać highlights the choice to remain at home rather than go somewhere else.

Yes, both are possible, but they are slightly different.

• zostać is perfective
• zostawać is imperfective

With woleć:

• wolę zostać w domu suggests I’d rather stay home in a given situation, or as a typical choice when this situation happens
• wolę zostawać w domu sounds more like a general repeated preference or habit

In this sentence, wolę zostać w domu is very natural because it sounds like: when I’m tired after work, I prefer to stay home in the evening.

Here w means in/at, and because this is a static location (not movement), it takes the locative case.

• nominative: dom = house/home
• locative: domu

So:

• w domu = at home / in the house

Compare:

• jestem w domu = I am at home
• idę do domu = I’m going home

So w domu is used for being somewhere, while do domu is used for movement toward home.

Most naturally, it sounds like a general habit or usual situation.

That is because:

• Po pracy szybko się męczę is in the present tense and sounds habitual
• wieczorem wolę zostać w domu then sounds like the usual result

So the overall meaning is something like:

• After work I get tired quickly, so in the evening I prefer to stay at home

Depending on context, Polish present tense can sometimes refer to a current situation more broadly, but without extra context this sounds like a regular pattern.

Yes. Polish allows fairly flexible word order, but changing the order changes the emphasis.

The given version is neutral and natural:

• Po pracy szybko się męczę, więc wieczorem wolę zostać w domu.

Possible alternatives include:

• Po pracy męczę się szybko, więc wieczorem wolę zostać w domu.
• Wieczorem wolę zostać w domu, bo po pracy szybko się męczę.

These are still understandable, but the focus shifts slightly.

For learners, the original sentence is a very good standard version to remember.