i japjie naon gwanggoga neomu manhaseo ilggi jogeum bulpyeonhaesseo.

A useful breakdown is:

이 잡지에 나온 광고가 / 너무 많아서 / 읽기 / 조금 / 불편했어

• 이 잡지에 나온 광고가 = the ads that appeared in this magazine
• 너무 많아서 = because there were too many
• 읽기 = reading it / to read
• 조금 불편했어 = was a little inconvenient / uncomfortable

So the whole sentence means something like:

There were too many ads in this magazine, so it was a little inconvenient to read.

Yes, 나오다 literally means to come out, but in Korean it is also commonly used for things that appear, are shown, or are featured somewhere.

So 잡지에 나온 광고 literally means the ads that came out in the magazine, but in natural English that becomes:

• the ads that appeared in the magazine
• the ads printed in the magazine
• the ads featured in the magazine

Here, 나온 is the past adnominal form of 나오다, so it modifies the noun 광고.

Here, 에 marks the place where something appears.

So:

• 잡지에 나오다 = to appear in a magazine
• TV에 나오다 = to appear on TV
• 신문에 나오다 = to appear in a newspaper

In this sentence, 이 잡지에 나온 광고 means ads that appeared in this magazine.

Because 광고 is not the object of 읽다 here. It is the subject of 많다.

The relevant part is:

광고가 너무 많아서 = because the ads were too many / because there were too many ads

So 가 marks 광고 as the thing being described by 많다.

If you used 광고를, it would sound like the ads were being directly acted on, which is not what is happening here.

Korean often does not mark plural when the meaning is already clear from context.

Here, 너무 많아서 already tells you there were many of them, so 광고 naturally means ads.

You could say 광고들이, but that would usually sound unnecessary here. Korean often prefers the simpler form.

Here it means too.

너무 can mean:

• very in casual modern speech
• too excessively in a more literal sense

In this sentence, because it is followed by a negative result:

너무 많아서 읽기 조금 불편했어
= There were too many, so it was inconvenient to read

So too many is the best translation here.

-아서/어서 connects two clauses and often shows cause or reason.

So:

• 광고가 너무 많아서 = because there were too many ads
• 읽기 조금 불편했어 = it was a little inconvenient to read

Together, it means the first part caused the second part.

In other words: Because there were too many ads, it was a little inconvenient to read.

읽기 is a nominalized form of the verb 읽다, so it turns to read / reading into a noun-like expression.

Here, 읽기 불편하다 means to be inconvenient to read or reading is inconvenient.

You could also say 읽는 것이 조금 불편했어, but that is a bit more explicit and slightly heavier.
읽기 조금 불편했어 sounds natural and concise in everyday Korean.

Yes, you can think of a particle as being omitted.

A fuller version could be:

• 읽기가 조금 불편했어
• sometimes also 읽기에 조금 불편했어

In casual speech, Korean often drops particles when the meaning is clear, so 읽기 조금 불편했어 sounds natural.

So this sentence is not ungrammatical; it is just slightly compressed and conversational.

불편하다 literally means something like to be uncomfortable or to be inconvenient.

In this sentence, it does not mean severe physical pain or anything dramatic. It means that reading the magazine was not very easy or pleasant because there were so many ads.

Good natural translations include:

• It was a little inconvenient to read
• It was a bit uncomfortable to read
• It was a little annoying to read

The exact English wording depends on tone, but inconvenient is a very safe choice.

It means reading the magazine was inconvenient.

Korean often leaves the object unstated when it is obvious from context. Since the sentence is talking about ads in this magazine, the understood idea is:

이 잡지를 읽기 조금 불편했어
= It was a little inconvenient to read this magazine

So the magazine is the implied thing being read.

했어 is the casual, informal past form.

The base adjective is 불편하다, and in the past tense it becomes 불편했어.

This style is used when speaking to friends, people younger than you, or in informal narration.
More polite versions would be:

• 불편했어요 = polite
• 불편했습니다 = formal

So the original sentence has a casual spoken tone.

Yes. A few natural variations are:

• 이 잡지에 나온 광고가 너무 많아서 읽기가 조금 불편했어.
• 이 잡지는 광고가 너무 많아서 읽기 불편했어.
• 이 잡지는 광고가 너무 많아서 읽기가 좀 불편했어.

These all express basically the same idea. The original sentence is already natural; the main differences are whether the speaker includes particles like 가 after 읽기, and whether they focus on the ads in the magazine or the magazine itself.