Learn Hardcore Spanish (Spain): Me duele el pecho cuando corro, pero mi médica dice que mis pulmones están bien. - My chest hurts when I run, but my doctor says my lungs are fine.

Me duele el pecho. = The chest hurts me / My chest hurts.
- me = to me (indirect object pronoun)
- duele = hurts (3rd person singular)
- el pecho = the chest (this is the grammatical subject)

So literally it is “The chest hurts to me”, but in English we say “My chest hurts”.

You can say Mi pecho duele, but it sounds unusual and marked, almost poetic or dramatic. In everyday speech, people say Me duele + [body part] almost all the time.

Why do we say el pecho (the chest) instead of mi pecho (my chest)?

When talking about body parts (and clothes), Spanish often uses the definite article (el / la / los / las) plus an indirect object pronoun, instead of a possessive:

Me duele la cabeza. = My head hurts.
Le duelen las piernas. = His/her legs hurt.

The person is already clear from the pronoun (me, te, le, etc.), so a possessive (mi, tu, su) is usually not needed.

So:

Me duele el pecho. (standard)
Me duele mi pecho. (usually sounds odd or overly emphatic)

Use the possessive with body parts when you’re really contrasting owners or when there’s no pronoun to show whose it is, e.g.:

Este es mi pecho, no el tuyo. = This is my chest, not yours.

What exactly does doler mean, and how is it conjugated in this type of sentence?

Doler literally means to hurt / to ache, but grammatically it behaves like gustar:

It agrees with the thing that hurts (the subject).
The person who feels the pain is an indirect object (with me, te, le, nos, os, les).

Examples:

Me duele el pecho. = My chest hurts.
- duele (singular) because el pecho is singular.
Me duelen los pies. = My feet hurt.
- duelen (plural) because los pies is plural.
A Juan le duele la espalda. = Juan’s back hurts.

Basic pattern:

[Indirect object pronoun] + duele / duelen + [body part]

Why is there no yo before corro? Why not cuando yo corro?

Spanish often drops subject pronouns (yo, tú, él, etc.) because the verb ending already shows who the subject is:

corro clearly means I run (1st person singular).
So cuando corro already means when I run.

You usually add yo only:

for emphasis or contrast:
- Cuando yo corro, me duele el pecho, pero cuando camino, no.
to avoid ambiguity (mainly in 3rd person).

Both are correct:

Cuando corro, me duele el pecho. (neutral, most common)
Cuando yo corro, me duele el pecho. (emphasizing I specifically)

Why is it mi médica and not mi médico? Is médica really used?

Yes, médica is widely used, especially in Spain, to refer to a female doctor.

médico = male doctor, or traditionally a generic doctor.
médica = female doctor.

In current usage (particularly in Spain and much of Latin America), many people prefer using the feminine form for professions when referring to a woman:

mi profesora (my female teacher) vs mi profesor
la jefa (the female boss) vs el jefe
mi médica (my female doctor) vs mi médico

So mi médica tells you:

the speaker’s doctor is a woman
the speaker is using gendered profession nouns in a modern, common way.

Why is it mis pulmones están bien and not something like son buenos?

Here están bien focuses on the current state/condition of the lungs:

estar + bien = to be fine / OK / in good condition at the moment.
ser + bueno = to be good (quality, morally good, or generally good/useful).

So:

Mis pulmones están bien. = My lungs are fine / There is nothing wrong with them.
Mis pulmones son buenos. sounds odd; we don’t normally talk about lungs being “good” in that general sense.

Estar + bien is very common in health contexts:

Estoy bien. = I’m fine.
Tu corazón está bien. = Your heart is fine.
Todo está bien. = Everything is fine.

Why do we use mis pulmones with mis, but el pecho without mi?

Great contrast to notice:

Me duele el pecho
- Uses doler
  - body part.
- The owner is shown by me, so Spanish uses the article (el pecho), not a possessive.
Mis pulmones están bien
- This is just [possessive] + noun + verb.
- There’s no indirect object pronoun referring to the owner.
- We are describing whose lungs and how they are, so the possessive mis is natural.

You could also say:

Los pulmones están bien.
if it’s already clear from context whose lungs you mean.
But mis pulmones makes it explicit that we are talking about my lungs.

Why is it corro (simple present) and not estoy corriendo (I am running)?

In Spanish, the simple present is used much more than in English. It often covers meanings where English uses present continuous:

Cuando corro, me duele el pecho.
= When I run / Whenever I run, my chest hurts.
(general, habitual situation)

You would use estoy corriendo mainly when stressing an action in progress right now:

Ahora mismo estoy corriendo y me duele el pecho.
= I’m running right now, and my chest hurts.

So in this sentence, corro is the natural choice to express a recurring situation, not just a single moment.

Why is the conjunction pero used, and not sino?

Both pero and sino can translate as but, but they’re used differently:

pero = but / however (adds or contrasts information)
sino = but rather / but instead (corrects or replaces a negated idea)

In the sentence:

Me duele el pecho cuando corro, pero mi médica dice que mis pulmones están bien.

We are not correcting a negation. We’re saying:

My chest hurts when I run, but at the same time my doctor says my lungs are fine.

Compare:

No me duele el pecho, sino la espalda.
= My chest doesn’t hurt, but rather my back (does).
Here we correct a negation, so sino is needed.

So pero is correct in the original sentence.

Can I also say El pecho me duele instead of Me duele el pecho?

Yes, El pecho me duele is grammatically correct, but the most common and neutral order is:

Me duele el pecho.

Word order in Spanish can change to adjust emphasis or rhythm:

Me duele el pecho.
Focus is on what hurts (the chest).
El pecho me duele.
Slightly more emphasis on the chest itself, often in contrast:
- El pecho me duele, pero la espalda no.

Both are understood; you’ll simply hear Me duele el pecho much more often.

Why does médica have an accent on the first é? What difference does it make?

The accent in médica is important because:

médica (with accent on mé) = female doctor (noun).
medica (no accent, stress naturally on di) = he/she medicates (from the verb medicar).

The written accent:

shows where the stress goes (MÉ-di-ca, not me-DI-ca),
and distinguishes words that would otherwise be spelled the same.

So in this sentence:

mi médica clearly means my (female) doctor, not my “medicates.”