Ystäväni kävi mittauttamassa verenpaineen apteekissa, vaikka hän tunsi olonsa hyväksi.

Ystävä means friend. The ending -ni is the possessive suffix meaning my, so ystäväni means my friend.

Finnish often marks possession with a suffix attached to the noun instead of using a separate word like my. So:

• ystävä = friend
• ystäväni = my friend

In more formal written Finnish, this kind of possessive suffix is very common.

This is a very common Finnish pattern.

• kävi is the past tense of käydä, which here means went or went to visit
• mittauttamassa is a form meaning to have something measured

Together, kävi mittauttamassa means something like went to have measured.

Finnish often uses käydä + verb in -massa/-mässä to express go and do something:

• kävin ostamassa leipää = I went to buy bread
• hän kävi tapaamassa ystävää = he/she went to meet a friend

So kävi mittauttamassa verenpaineen means went to have his/her blood pressure measured.

This is an important difference.

• mitata = to measure
• mittauttaa = to have something measured or to get something measured

So:

• Hoitaja mittasi verenpaineen = The nurse measured the blood pressure
• Hän mittautti verenpaineen = He/she had the blood pressure measured

The verb mittauttaa is a causative verb. It means the subject does not do the measuring personally; someone else does it for them.

Because it is the object of the action, and here the action is seen as complete: the person had the blood pressure measured.

In Finnish, a completed, definite object often appears in the total object form. In this sentence, verenpaineen is that form.

A small extra detail: the basic dictionary form is verenpaine = blood pressure, and its object/genitive-like form is verenpaineen.

So here:

• verenpaine = blood pressure
• verenpaineen = the blood pressure, as a completed object

Because käydä often works with a location form meaning at/in a place, not the movement form meaning into a place.

• apteekissa = in/at the pharmacy
• apteekkiin = into the pharmacy

With käydä, Finnish usually focuses on visiting a place, so the location form is natural:

• kävin apteekissa = I went to the pharmacy / I visited the pharmacy

If you used mennä, then apteekkiin would be natural:

• menin apteekkiin = I went into/to the pharmacy

So kävi apteekissa is the normal way to say went to the pharmacy in this kind of context.

Vaikka means although, even though, or though.

It introduces a contrast:

• Ystäväni kävi mittauttamassa verenpaineen apteekissa
• vaikka hän tunsi olonsa hyväksi

So the idea is: the friend went to have their blood pressure checked even though they felt fine.

Because Finnish has two different verbs here:

• tuntea = to feel, to know by feeling
• tuntua = to feel, to seem

In this sentence, Finnish uses the expression tuntea olonsa..., literally something like to feel one’s state/condition...

So:

• hän tunsi olonsa hyväksi = he/she felt good

A different but related pattern is:

• hänestä tuntui hyvältä = it felt good to him/her

Both can be translated naturally into English as he/she felt good, but the Finnish structures are different.

It comes from olo, which means state, feeling, or condition.

So tuntea olonsa is an idiomatic Finnish expression meaning to feel in the sense of to feel oneself in a certain state.

• olo = state, feeling
• olonsa = his/her own state, with a possessive ending

In practice, you do not need to translate it word for word every time. Just learn the whole pattern:

• tuntea olonsa hyväksi = to feel good
• tuntea olonsa väsyneeksi = to feel tired
• tuntea olonsa sairaaksi = to feel sick

Because this expression uses a specific pattern:

• tuntea olonsa + adjective in the translative case

The translative ending is -ksi, so:

• hyvä = good
• hyväksi = into/as good, but here simply part of the idiom

So:

• tuntea olonsa hyväksi = to feel good

This is different from another common pattern:

• tuntua hyvältä = to feel good

So both are possible in Finnish, but they belong to different structures:

• hän tunsi olonsa hyväksi
• hänestä tuntui hyvältä

Both can mean roughly the same thing in English.

It can mean either one.

Finnish hän is gender-neutral, so it means he or she depending on context. The language does not force you to specify gender here.

So in this sentence, hän could refer to:

• he
• she

Only context tells you which one is meant.

Finnish word order is fairly flexible, but the given order is neutral and natural.

• Ystäväni kävi mittauttamassa verenpaineen apteekissa, vaikka hän tunsi olonsa hyväksi.

This sounds like a normal, unmarked sentence.

You can move elements for emphasis, but then the focus changes. For example:

• Apteekissa ystäväni kävi mittauttamassa verenpaineen...

This puts more emphasis on at the pharmacy.

So the sentence is not completely fixed, but the original version is probably the best basic order for a learner to use.