Después de la pastilla, pude comer una pera sin dolor.

Después usually needs de before a noun or pronoun.

• después de la pastilla = after the pill
• después de comer = after eating
• después by itself usually means afterwards / later

So in this sentence, después de la pastilla is the normal structure because it is followed by a noun phrase.

Yes. Pastilla usually means pill, tablet, or sometimes lozenge, depending on context. In this sentence, it most naturally means some kind of medicine.

In Spain, pastilla is a very common everyday word for a pill or tablet.

Using la suggests the pill is specific and already known from the context.

So this sounds like:

• the pill we were talking about
• the pill the speaker took
• the medicine that was relevant in the situation

If you said una pastilla, it would sound less specific: a pill.

Literally, it is after the pill, but in real use it often implies after taking the pill or after the pill started working.

Spanish often leaves that kind of detail unstated if the context makes it obvious.

A more explicit version would be:

• Después de tomar la pastilla... = After taking the pill...

But the original sentence is natural and idiomatic.

Pude is the preterite of poder, and here it means I managed to / I was able to at a specific moment or in a completed situation.

• pude comer = I was able to eat / I managed to eat
• podía comer = I could eat / I was able to eat in a more general, ongoing, or habitual sense

Because the sentence describes a completed event after the pill, pude fits very well.

Compare:

• Después de la pastilla, pude comer una pera. = After the pill, I managed to eat a pear.
• Cuando estaba mejor, podía comer fruta. = When I was better, I could eat fruit.

Because poder is a modal verb, and it is followed by an infinitive.

So:

• pude comer = I was able to eat
• puedo hablar = I can speak
• no pudo dormir = he/she couldn’t sleep

This works very much like English can / could / be able to + verb.

Pera means pear, and it is a feminine singular noun, so it takes una.

• una pera
• la pera

If it were masculine, it would use un or el, but pera is feminine.

Sin is often followed by a noun without an article when speaking in a general sense.

So:

• sin dolor = without pain
• sin problema = without problem / with no problem
• sin miedo = without fear

Sin el dolor would sound more specific, as if referring to a particular pain already identified. Here the general expression sin dolor is the natural choice.

Yes, most naturally it means the speaker was able to eat the pear without pain while doing so.

So the idea is:

• After the pill, eating the pear did not hurt.

It could also be understood more broadly as pain-free, but it most directly relates to the action of comer.

Spanish often omits subject pronouns because the verb ending already shows the subject.

• pude already tells you it means I was able
• so yo pude is possible, but usually unnecessary

You would include yo only for emphasis, contrast, or clarity:

• Yo pude comer, pero él no. = I was able to eat, but he wasn’t.

It is not always strictly necessary, but it is very natural here.

The comma helps separate the introductory phrase from the main clause:

• Después de la pastilla, pude comer una pera sin dolor.

Without the comma, the sentence is still understandable:

• Después de la pastilla pude comer una pera sin dolor.

In writing, many people would include the comma because the opening phrase is fairly long and sets the time/context clearly.

Yes, but the original order is very natural.

Original:

• Después de la pastilla, pude comer una pera sin dolor.

Other possible versions:

• Pude comer una pera sin dolor después de la pastilla.
• Sin dolor, pude comer una pera después de la pastilla.

The original sounds best because it first gives the context (after the pill) and then the result (I was able to eat a pear without pain).

A Spain pronunciation would be roughly:

• después → dehs-PWES
• pastilla → pahs-TEE-ya
• pude → POO-deh
• pera → PEH-ra
• dolor → doh-LOR

A couple of helpful points:

• ll in pastilla is pronounced like y in most of Spain today.
• r in pera is a tapped r, not the English r.
• Stress falls on -pués, -ti-, pu-, pe-, and -lor respectively.

Yes, but it means something slightly different in structure and sounds more explicit.

• sin dolor = without pain
• sin que me doliera = without it hurting me / without it causing me pain

So you could say:

• Después de la pastilla, pude comer una pera sin que me doliera.

That version is grammatically fine, but the original sin dolor is shorter and more natural in many everyday situations.