A médica disse que eu não posso mexer o braço hoje.

Médica is the feminine form of médico. It tells you the doctor is a woman.

• o médico = the male doctor
• a médica = the female doctor

So the sentence specifically says the speaker is talking about a female doctor.

In Portuguese, it is very normal to use a definite article before a noun like médica when you mean a specific person.

So:

• a médica = the doctor
• uma médica = a doctor

Here, a médica means a specific doctor that both speaker and listener can identify from context.

Disse is the past tense of dizer = to say / to tell.

• dizer = to say
• disse = said

Que here means that.

So:

• disse que... = said that...

This is a very common structure in Portuguese for reported speech.

Yes, Portuguese often allows the subject pronoun to be omitted, because the verb ending already shows the person.

So both of these are possible:

• A médica disse que eu não posso mexer o braço hoje.
• A médica disse que não posso mexer o braço hoje.

Both are natural.

Including eu can add clarity or emphasis, especially inside a longer sentence.

In Portuguese, não normally comes directly before the verb.

So:

• posso = I can
• não posso = I cannot / I can’t

That placement is the standard one.
You will very often see:

• não sei = I don’t know
• não quero = I don’t want
• não posso = I can’t

Because the doctor’s statement is still true today, at the time the speaker is talking about it.

• disse = she said
• eu não posso... hoje = I can’t... today

Portuguese does not always shift the tense backward the way English often does in reported speech. If the situation is still valid now, the present tense is very natural.

So this sentence is basically:

• The doctor said that I can’t move my arm today.

In English, many speakers might also say said that I couldn’t, but in Portuguese the present here is completely normal.

Here, mexer o braço means to move the arm.

But mexer is a flexible verb. Depending on context, it can mean things like:

• move
• stir
• fiddle with
• mess with
• handle

Compared with mover:

• mover = a more direct, neutral to move
• mexer = often suggests moving around, wiggling, stirring, or manipulating something

With a body part, mexer o braço sounds very natural in Brazilian Portuguese.

Portuguese often uses the definite article with body parts when the owner is already obvious.

So instead of saying my arm, Portuguese frequently says just the arm:

• machuquei a mão = I hurt my hand
• lavei o rosto = I washed my face
• mexer o braço = move my arm / the arm

Because the subject is eu, it is already clear whose arm is being discussed.

Yes. Portuguese allows some flexibility with adverbs like hoje.

All of these can work, though they may sound slightly different in emphasis:

• A médica disse que eu não posso mexer o braço hoje.
• A médica disse que hoje eu não posso mexer o braço.
• Hoje, a médica disse que eu não posso mexer o braço.

The original version is very natural. Putting hoje at the end keeps the sentence straightforward and conversational.

A rough English-friendly guide:

• médica ≈ MEH-jee-ka
  The stress is on mé because of the accent mark.

• disse ≈ JEE-see
  In Brazilian Portuguese, d before i often sounds a bit like the j in jeep.

• mexer ≈ meh-SHER
  The x here sounds like sh.

• braço ≈ BRAH-soo
  The ç sounds like s.

These are only approximations, but they are useful for getting close.

The accent mark in médica shows the stressed syllable:

• MÉ-di-ca

Without the accent, a learner might stress it incorrectly. In Portuguese, accent marks are important because they help show pronunciation and sometimes distinguish words.

Yes. You could say:

• A médica me disse que eu não posso mexer o braço hoje.

That means The doctor told me that I can’t move my arm today.

The original sentence without me is still fine. It just focuses on what the doctor said, without explicitly mentioning the listener of that statement. Adding me makes it more explicit that the doctor said it to me.

Sometimes, yes, but disse is better here.

• disse = said / told
• falou = spoke / said

A médica falou que... is common in everyday Brazilian Portuguese, especially in speech, but disse que... is a bit more standard and precise in this kind of sentence.

So:

• A médica disse que... = very natural and standard
• A médica falou que... = also common in conversation

Both can be understood, but disse is the safer choice for learners.