Meu braço dói, então vou colocar gelo agora.

In Brazilian Portuguese, both meu braço and o meu braço are possible, but meu braço is very common and natural.

With body parts, Portuguese often uses either:

• a possessive: meu braço
• or a definite article when the owner is already clear from context: O braço dói

Using meu braço is straightforward and sounds completely normal here.

Dói comes from the verb doer, which means to hurt.

In this sentence, meu braço is the thing that hurts, so it is the grammatical subject:

• Meu braço dói. = My arm hurts.

This is similar to English My arm hurts, but unlike English, you should think of doer as a verb where the painful thing is usually the subject.

Other examples:

• Minha cabeça dói. = My head hurts.
• As pernas doem. = My legs hurt.

Notice:

• singular: dói
• plural: doem

Because doer is an irregular verb.

In the present tense:

• eu doo
• você/ele/ela dói
• nós doemos
• vocês/eles/elas doem

So with meu braço (third-person singular), you need dói.

The accent matters here: dói is pronounced as one stressed syllable with a glide at the end, roughly like DOY.

Yes. Meu braço está doendo is also very natural.

There is a small difference in feel:

• Meu braço dói. = My arm hurts.
• Meu braço está doendo. = My arm is hurting.

In everyday Brazilian Portuguese, both can describe pain happening now.
The present tense (dói) is often used for a current state, so the original sentence sounds perfectly natural.

The accent shows the stress and helps distinguish pronunciation.

Dói is stressed on that syllable, and the vowel is pronounced openly.
A learner can think of it approximately as DOY.

Without the accent, the spelling would not represent the standard form of the word.

Here, então means so, therefore, or then.

It links the two ideas:

• Meu braço dói = my arm hurts
• então vou colocar gelo agora = so I’m going to put/apply ice now

So it expresses a consequence: My arm hurts, so I’m going to put ice on it now.

Because então is connecting two clauses:

• Meu braço dói
• então vou colocar gelo agora

In writing, a comma before então is very common and natural when it means so/therefore.

Vou colocar is the very common ir + infinitive future construction.

It literally means I am going to put, but in normal speech it often simply means I’ll put / I’m going to put.

So:

• vou colocar = I’m going to put / I’ll put

Portuguese also has a simple future:

• colocarei

But in everyday Brazilian Portuguese, vou colocar is much more common in conversation.

Literally, it means to put ice.

In context, it means to put/apply ice on the arm. Portuguese often leaves out information that is obvious from context.

So:

• vou colocar gelo agora = I’m going to put/apply ice now
• more explicit: vou colocar gelo no braço agora = I’m going to put ice on my arm now

Both are fine, but the shorter version sounds natural when everyone already knows what you mean.

Because gelo is being used as a general mass noun here, like ice in English.

So:

• vou colocar gelo = I’m going to put/apply ice

If you added an article, it could sound more specific depending on context:

• o gelo = the ice
• um gelo is generally not how you would say some ice here

The version without an article is the most natural in this sentence.

You could, but it changes the feeling.

Vou colocar o gelo suggests a more specific, already identified ice, like:

• the ice we prepared
• the ice pack
• the ice you mentioned

If you just mean I’m going to put some ice on it, then vou colocar gelo is more natural.

It can, but it does not have to.

Portuguese often omits information that is obvious from context. Since the first part already mentions meu braço, the listener can easily understand where the ice is going.

So both are possible:

• Meu braço dói, então vou colocar gelo agora.
• Meu braço dói, então vou colocar gelo no meu braço agora.

The second one is clearer but more repetitive. The first one sounds more natural in many real conversations.

Yes, and that is exactly what happened here.

Portuguese often drops subject pronouns when the verb already makes the subject clear.

• (Eu) vou colocar gelo agora.

Because vou clearly shows I, the pronoun eu is unnecessary.

This is very common in Portuguese.

Agora means now.

It tells you the action will happen immediately:

• vou colocar gelo agora = I’m going to put ice on it now

Without agora, the sentence would still make sense:

• Meu braço dói, então vou colocar gelo.

Adding agora makes it more immediate and natural in spoken language.

Braço is pronounced approximately like BRAH-soo in Brazilian Portuguese, though the final vowel is lighter than English oo.

A few points:

• ç sounds like s
• the stress is on bra
• braço = BRA-so

So:

• braço → BRA-so

Also notice that ç is only used before a, o, u to keep the s sound:

• braço
• but before e or i, plain c already has that sound:
  • cidade

Então is roughly pronounced en-TOWN, but with a nasal ending.

Important parts:

• stress on the second syllable: tão
• ão is a nasal sound that English does not have exactly

A rough learner-friendly approximation is:

• en-TOW̃

You do not pronounce a clear n at the end. The vowel becomes nasal instead.

Not with the same meaning.

• então = so / therefore
• porque = because

Your sentence gives a cause and then a result:

• My arm hurts, so I’m going to apply ice.

That needs então.

If you used porque, you would be expressing reason in a different structure, for example:

• Vou colocar gelo agora porque meu braço dói.
• I’m going to put ice on it now because my arm hurts.

That is also correct, but it is a different sentence structure.

Yes, it sounds natural and idiomatic.

A Brazilian speaker might also say:

• Meu braço tá doendo, então vou colocar gelo agora.
• Meu braço dói, então vou pôr gelo agora.
• Tô com dor no braço, então vou colocar gelo agora.

But your original sentence is completely normal and correct: Meu braço dói, então vou colocar gelo agora.