uisaneun yeomjeungi simhaji anhaseo jusaneun an majado doendago haesseo.

는 marks 의사 as the topic: as for the doctor or the doctor, [he/she]...

In this sentence, 의사는 sets up who is making the statement. It is not strongly emphasizing the doctor as the grammatical subject; it is more like introducing the doctor as the topic of discussion.

So the nuance is something like:

• As for the doctor, he/she said...

If you used 의사가, that would sound more like you are specifically emphasizing that the doctor (rather than someone else) said it.

Here, 염증이 심하지 않아서 means because the inflammation is not severe.

이/가 is used because 염증 is the subject of 심하다 (to be severe). The sentence is simply describing the condition of the inflammation.

• 염증이 심하다 = the inflammation is severe
• 염증이 심하지 않다 = the inflammation is not severe

If you said 염증은, it could sound more contrastive, like as for the inflammation, it’s not severe—possibly implying comparison with something else.

It breaks down like this:

• 심하다 = to be severe
• 심하지 않다 = to not be severe
• 심하지 않아서 = because it is not severe / since it is not severe

More specifically:

• 심하- = stem
• -지 않다 = formal negative pattern
• -아서 / -어서 = because / so

So 심하지 않아서 literally means because it is not severe.

This is a very common way to express a reason in Korean.

Both 안 and -지 않다 make a sentence negative, but they are used a little differently.

1. -지 않다

This is a standard grammatical negation attached to the verb/adjective stem:

• 심하다 → 심하지 않다

This form is especially common with adjectives like 심하다.

2. 안

This is an adverb meaning not, placed before the verb:

• 맞다 → 안 맞다

So:

• 심하지 않아서 = because it is not severe
• 안 맞아도 되다 = it is okay not to get it / no need to get it

In many cases, both negatives are possible, but one may sound more natural depending on the word. Here, the sentence sounds very natural as written.

Yes—literally, 맞다 can mean to be hit. But in Korean, it is also the normal verb used for getting certain medical treatments, especially injections and vaccines.

So:

• 주사를 맞다 = to get an injection / to get a shot
• 백신을 맞다 = to get a vaccine

This is just the standard Korean expression. Even though it may feel strange from an English point of view, it is the natural verb to use.

주사는 uses 는 after 주사 to give it a contrastive or topical nuance.

So 주사는 안 맞아도 된다 feels like:

• as for injections, you don’t need to get one
• or at least a shot isn’t necessary

This can imply mild contrast, even if nothing else is stated directly. For example, the doctor may be saying:

• medicine might still be needed,
• treatment might still be needed,
• but an injection, specifically, is not necessary.

If you said 주사를 안 맞아도 된다, that would still be correct, but 주사는 adds a slight sense of as for the shot...

This is a very useful grammar pattern.

Form:

• verb stem + 아/어도 되다

It means:

• it is okay to...
• it is allowed to...
• sometimes it is not necessary to not do X depending on negation

Here:

• 맞다 = get a shot
• 안 맞아도 되다 = it is okay not to get a shot

In natural English, that often becomes:

• you don’t have to get a shot
• there’s no need for an injection

So this is not just permission. In context, it often means lack of necessity.

This is reported speech: said that...

Breakdown:

• 되다 = to become / to be okay / to be allowed
• 된다 = plain form
• 된다고 = that it is okay / that it will do
• 했어 = said

So:

• 안 맞아도 된다고 했어 = [someone] said that [you] don’t have to get a shot

This -다고 하다 pattern is very common for reporting what someone said.

Examples:

• 간다고 했어 = [someone] said they’re going
• 괜찮다고 했어 = [someone] said it’s okay
• 필요 없다고 했어 = [someone] said it’s not necessary

Korean often leaves out subjects when they are understood from context.

In this sentence, the person who doesn’t need the shot is not explicitly stated. It could be:

• you
• I
• the patient
• he/she

depending on the situation.

So the sentence naturally relies on context. In English, we usually have to add the subject, but Korean often does not.

That is very normal and common.

했어 is the casual/informal polite level? Not exactly—it is the casual, non-polite style.

Speech levels:

• 했어 = casual, used with friends, close people, children, or in diary-style narration
• 했어요 = polite, everyday standard conversation
• 했습니다 = formal

So this sentence sounds like something you would say casually to someone close:

• The doctor said the inflammation isn’t that severe, so you don’t need a shot.

If you wanted a polite version, you could say:

• 의사는 염증이 심하지 않아서 주사는 안 맞아도 된다고 했어요.

Yes. The doctor’s reported message is:

• 염증이 심하지 않아서 주사는 안 맞아도 된다
• Because the inflammation isn’t severe, you don’t need a shot

Then the speaker adds:

• ...고 했어
• ...said that

So the overall structure is:

• 의사는 = as for the doctor,
• [염증이 심하지 않아서 주사는 안 맞아도 된다]고 했어 = said that because the inflammation isn’t severe, a shot isn’t necessary

This kind of long quoted clause before -고 하다 is extremely common in Korean.

In this sentence, -아서/어서 is expressing a reason: because / since.

So:

• 염증이 심하지 않아서 주사는 안 맞아도 된다 = Because the inflammation is not severe, you don’t need a shot

While -아서/어서 can sometimes feel like a simple connection (and so, so), here the cause-and-result meaning is the natural one.

The logic is:

1. the inflammation is not severe
2. therefore, an injection is unnecessary

So because is the best way to understand it here.