Learn Hardcore Greek: Πάω πίσω στο σπίτι τώρα.

Greek usually leaves out subject pronouns when they are obvious from the verb ending.
The form πάω is first person singular (I), so Εγώ (I) is understood:

Πάω πίσω στο σπίτι τώρα. = (Εγώ) πάω πίσω στο σπίτι τώρα.

You only add Εγώ when you want to emphasize I specifically, e.g. Εγώ πάω πίσω στο σπίτι τώρα = I’m the one who is going back home now.

What exactly does πάω mean here, and is it different from πηγαίνω?

Πάω means I go / I’m going. It is the everyday, colloquial form of πηγαίνω, and in practice they usually mean the same thing.

πάω – more common in spoken Greek
πηγαίνω – slightly more formal or “full” form

In English we distinguish I go (simple) and I’m going (continuous), but in Greek the present tense πάω can express both, depending on context:

Πάω πίσω στο σπίτι τώρα. = I’m going back home now.
Κάθε μέρα πάω στο σπίτι στις πέντε. = Every day I go home at five.

What does πίσω mean here? Does it mean back or behind?

Πίσω can mean both back and behind, but in this sentence it clearly means back (to a previous place):

Πάω πίσω στο σπίτι τώρα. = I’m going back home now.

If you wanted to say behind the house, you would need από:

Πάω πίσω από το σπίτι. = I’m going behind the house.

So πίσω στο σπίτι is understood as “back to the house/home”, not “behind the house.”

Is πίσω necessary? What changes if I just say Πάω στο σπίτι τώρα?

You can absolutely say:

Πάω στο σπίτι τώρα. = I’m going home now.

Without πίσω, the sentence simply means you are going home; it does not say anything about returning.
With πίσω, you add the nuance that you are going back to a place where you were before:

Πάω στο σπίτι τώρα. – I’m going home now (neutral).
Πάω πίσω στο σπίτι τώρα. – I’m going back home now (I was away and I’m returning).

Why is it στο σπίτι and not just σπίτι?

Στο is σε + το and means to the / at the.
So:

στο σπίτι = to the house / at the house

Both Πάω στο σπίτι τώρα and Πάω σπίτι τώρα are correct, but there is a slight nuance:

Πάω σπίτι τώρα. – very idiomatic for I’m going home now (destination is “home”).
Πάω στο σπίτι τώρα. – a bit more like “I’m going to the house now”, focusing a little more on the place as a location/building.

In everyday speech, both are widely used and often overlap in meaning.

What exactly does στο mean grammatically?

Στο is a contraction of:

σε (to, in, at) + το (the – neuter, singular, accusative)

So στο σπίτι literally is to the house.
Grammatically:

σε = preposition
το = definite article (the)
σπίτι = neuter noun (house, home), accusative case here as the destination

Can I say στο σπίτι μου to mean to my home? Is that more natural?

Yes:

Πάω στο σπίτι μου τώρα. = I’m going to my home now.

In Greek, σπίτι without μου often already implies my home, if context is clear:

Πάω σπίτι. – I’m going home (usually your own home).

Adding μου (my) makes it explicit or adds emphasis/clarity, for example if you want to contrast it with someone else’s house:

Δεν πάω στο δικό σου σπίτι, πάω στο σπίτι μου.
I’m not going to your house, I’m going to my house.

Can I move τώρα to another place in the sentence?

Yes. All of these are grammatically correct:

Πάω πίσω στο σπίτι τώρα.
Τώρα πάω πίσω στο σπίτι.
Πάω τώρα πίσω στο σπίτι.

The main meaning stays the same: I’m going back home now.

Placing τώρα at the beginning (Τώρα πάω…) can slightly highlight now.
Placing it at the end (…σπίτι τώρα) feels very natural in speech and is very common.

Is Πάω πίσω στο σπίτι τώρα formal or informal?

It is neutral and very typical for everyday spoken Greek.
For something a bit more formal or careful, you might hear:

Τώρα πηγαίνω πίσω στο σπίτι.
Τώρα επιστρέφω στο σπίτι.

But Πάω πίσω στο σπίτι τώρα is perfectly fine in almost any casual or neutral context.

Can I change the order of πίσω and στο σπίτι? For example, Πάω στο σπίτι πίσω?

In this meaning (back home), Greek normally puts πίσω before the στο σπίτι phrase:

✅ Πάω πίσω στο σπίτι τώρα.

Πάω στο σπίτι πίσω sounds unnatural or confusing in standard modern Greek.
If πίσω stands alone as an adverb, you’d normally just say:

Πάω πίσω. – I’m going back. / I’m going to the back.

So, for go back home, stick with Πάω πίσω στο σπίτι.

How do you pronounce the words in this sentence?

Approximate pronunciation (using English letters, stressed syllables in CAPS):

Πάω → PA-o (two syllables; the ά is stressed; in fast speech it can sound close to PA)
πίσω → PEE-so (stress on PI)
στο → sto (like stoh)
σπίτι → SPEE-tee (stress on SPI)
τώρα → TO-ra (stress on TO, with o as in not but a bit shorter)

Each word in Greek has exactly one stressed syllable, marked by the accent (ά, ί, ό, etc.).

Are there other common ways to say I’m going back home now in Greek?

Yes, some very natural alternatives are:

Γυρίζω σπίτι τώρα. – I’m returning home now.
(Very common, everyday speech; γυρίζω = I return, I come back.)
Γυρνάω σπίτι τώρα. – Same as above, another common form of γυρίζω.
Επιστρέφω στο σπίτι τώρα. – I’m returning home now.
(More formal/neutral, e.g. in writing or careful speech.)

All of these can be used instead of Πάω πίσω στο σπίτι τώρα, depending on your style and the context.