Ο πονοκέφαλος δεν έχει φύγει ακόμα.

Greek normally uses the definite article with nouns much more often than English does.

So ο πονοκέφαλος literally means the headache, but in context it often naturally refers to the headache I have / the headache we’re talking about.

Greek does not usually say my here unless you specifically want to emphasize possession:

• Ο πονοκέφαλός μου δεν έχει φύγει ακόμα. = My headache hasn’t gone away yet.

Without μου, the meaning is still perfectly natural if the context already makes it clear whose headache it is.

Πονοκέφαλος is a masculine singular noun meaning headache.

In this sentence it is in the nominative case because it is the subject of the sentence.

You can tell it is masculine singular here from:

• the article ο
• the noun ending -ος (which is very often, though not always, masculine)

So:

• ο πονοκέφαλος = the headache as the subject

Δεν is the normal negation word for statements in Modern Greek. It means not.

It comes before the verb phrase:

• δεν έχει φύγει = has not gone

So the structure is:

• Ο πονοκέφαλος = subject
• δεν = negation
• έχει φύγει = verb phrase
• ακόμα = yet / still

A useful rule: in ordinary statements, δεν goes before the finite verb.

Έχει φύγει is the present perfect.

It is formed with:

• έχει = has
• φύγει = the perfective verb form used here after έχω

So:

• έχει φύγει = has gone / has left
• δεν έχει φύγει ακόμα = hasn’t gone yet

This tense is used because the sentence talks about a situation that started in the past and is still relevant now: the headache is still here now.

Because Greek is using the perfective form here, not the ordinary present-tense form.

Compare:

• φεύγει = is leaving / leaves / goes away
  (present)
• έχει φύγει = has gone / has gone away
  (present perfect)

So in this sentence Greek is not saying the headache is going away. It is saying the headache has not gone away yet.

That is why the form is φύγει, not φεύγει.

It plays a role similar to an English past participle in the perfect, but it is not exactly the same kind of form as in English.

In Modern Greek, the perfect is usually made with:

• έχω
  • a fixed verb form such as φύγει, γράψει, δει

So:

• έχω φύγει = I have left
• έχει φύγει = he/she/it has left

This second part does not change for gender or number the way an adjective would. It is a fixed verb form used in the perfect construction.

In negative sentences, ακόμα often means yet.

So:

• δεν έχει φύγει ακόμα = hasn’t gone away yet

In other contexts, ακόμα can also mean still or even depending on the sentence.

For example:

• Είναι ακόμα εδώ. = He/She is still here.

So the exact English translation depends on context. In this sentence, yet is the most natural choice.

Yes. Ακόμα and ακόμη are both correct.

In everyday speech, ακόμα is very common.
Ακόμη can sound a bit more formal or careful, but both are standard.

So these both work:

• Ο πονοκέφαλος δεν έχει φύγει ακόμα.
• Ο πονοκέφαλος δεν έχει φύγει ακόμη.

They mean the same thing here.

Putting ακόμα at the end is very natural and common.

• Ο πονοκέφαλος δεν έχει φύγει ακόμα.

Greek word order is fairly flexible, but different positions can change emphasis.

For example:

• Ακόμα δεν έχει φύγει ο πονοκέφαλος.
  = The headache still hasn’t gone away.

This version gives more emphasis to still/yet.

So the original order is neutral and very natural.

Yes. In Greek, φεύγω is very natural for symptoms, pain, and similar problems.

So:

• Ο πονοκέφαλος έφυγε. = The headache went away.
• Ο πόνος δεν φεύγει. = The pain isn’t going away.

Even though the basic meaning of φεύγω is leave/go away, Greek uses it idiomatically for things like headaches, pain, fever, and other unpleasant conditions.

You probably could say it in some contexts, but it means something a bit different.

• Ο πονοκέφαλος δεν έχει φύγει ακόμα
  = The headache hasn’t gone away yet.
  This focuses on the result up to now.

• Ο πονοκέφαλος δεν φεύγει ακόμα
  = closer to The headache isn’t going away yet / still isn’t going away.
  This sounds more like an ongoing process.

In this kind of everyday situation, δεν έχει φύγει ακόμα is the more natural way to express hasn’t gone away yet.

Normally, no—not in a neutral full sentence like this.

Greek usually wants the article here:

• Ο πονοκέφαλος δεν έχει φύγει ακόμα.

Without the article, it would sound incomplete, unusual, or very context-dependent. Greek uses bare nouns less freely than English does.

So for a normal sentence, keep ο.

You would usually say:

• Ο πονοκέφαλός μου δεν έχει φύγει ακόμα.

That is:

• ο πονοκέφαλος = the headache
• μου = my

Because of Greek stress rules, πονοκέφαλος becomes πονοκέφαλός before μου.

So:

• Ο πονοκέφαλός μου δεν έχει φύγει ακόμα. = My headache hasn’t gone away yet.

A rough pronunciation is:

o po-no-KE-fa-los den E-hi FEE-yi a-KO-ma

A few helpful notes:

• χ in έχει is the Greek sound heard in words like the German Bach or Scottish loch
• γ in φύγει here sounds like a soft y sound because it comes before ει
• the stressed syllables are:
  • πονοκέφαλος
  • έχει
  • φύγει
  • ακόμα

So the rhythm is: Ο πονοΚΕφαλος δεν Εχει ΦΥγει αΚΟμα.