isya ga kaita syohousen wo motte, yakuzaisi no tokoro he ikimasita.

Because 書いた 処方箋 is a noun-modifying clause: it means the prescription that the doctor wrote.

In Japanese, a verb in plain form can directly come before a noun and describe it.

• 医者が書いた処方箋 = the prescription that the doctor wrote

Even though 書いた is past tense, it does not make the whole sentence past by itself. It only tells you that the writing happened before the prescription was taken to the pharmacist.

This is very natural in Japanese:

• 昨日買った本 = the book I bought yesterday
• 友だちが作ったケーキ = the cake my friend made

In 医者が書いた処方箋, the doctor is the subject of the verb 書いた.

So:

• 医者が書いた = the doctor wrote

Inside a relative clause like this, が is very common for marking the subject.

If you are thinking, Why not は?, the reason is that は usually marks the topic of the larger sentence, while here 医者 is specifically the subject of the smaller clause modifying 処方箋.

So the structure is:

• [医者が書いた] 処方箋
• [the doctor wrote] prescription

Japanese usually does not need a word like that, which, or who in relative clauses.

English:

• the prescription that the doctor wrote

Japanese:

• 医者が書いた処方箋

The whole clause 医者が書いた comes directly before the noun 処方箋.

This is one of the big structural differences from English:

• English often uses that/who/which
• Japanese usually just places the descriptive clause before the noun

持って is the て-form of 持つ, which means to hold, to carry, or to bring.

Here, 処方箋を持って means something like:

• holding the prescription
• bringing the prescription with them
• with the prescription in hand

The て-form connects this action to the next one:

• 処方箋を持って、薬剤師のところへ行きました。 = (I) took the prescription and went to the pharmacist.

It does not necessarily mean two completely separate actions. It often gives the sense of going while having it with you.

Because 処方箋 is not the object of 行きました. It is the object of 持って.

Break it up like this:

• 処方箋を持って = holding/bringing the prescription
• 薬剤師のところへ行きました = went to the pharmacist

So:

• を marks what was carried
• へ marks where the person went

This is a very common pattern in Japanese:

• かばんを持って出かける = go out carrying a bag
• 傘を持って学校へ行く = go to school with an umbrella

ところ literally means place, so 薬剤師のところ means the pharmacist’s place.

In context, it usually means:

• the place where the pharmacist is
• the pharmacist’s counter/work area
• simply the pharmacist

So:

• 薬剤師のところへ行きました = went to the pharmacist literally, went to the pharmacist’s place

This pattern is common:

• 先生のところへ行く = go to the teacher
• 友だちのところに行く = go to a friend’s place / go to see a friend
• 病院の受付のところ = the reception area of the hospital

Because in Japanese, you normally go to a place, not directly to a person with 行く.

So 薬剤師へ行く sounds unnatural, since 薬剤師 is a person, not a destination place.

To express go to the pharmacist, Japanese often uses:

• 薬剤師のところへ行く = go to the pharmacist’s place / go see the pharmacist

This is similar to:

• 医者のところへ行く = go to the doctor
• 部長のところへ行く = go to the manager

Both へ and に can mark direction with 行く, and in many cases both are possible.

• 薬剤師のところへ行きました
• 薬剤師のところに行きました

Both are natural.

The general difference is:

• へ emphasizes direction toward
• に emphasizes the destination

In everyday speech, the difference is often small. In this sentence, へ gives a slightly directional feeling: went over to the pharmacist.

The subject is omitted because Japanese often leaves it out when it is understood from context.

So the sentence likely means:

• I went to the pharmacist with the prescription the doctor wrote or
• He/She went to the pharmacist with the prescription the doctor wrote

Japanese does this constantly. If the subject is obvious, it is usually not repeated.

So instead of saying:

• 私は医者が書いた処方箋を持って、薬剤師のところへ行きました。

Japanese often just says:

• 医者が書いた処方箋を持って、薬剤師のところへ行きました。

Because the whole sentence is describing a completed event in the past: the person went to the pharmacist.

• 行きました = went

Notice that there are two past forms in the sentence, but they do different jobs:

• 書いた = the doctor wrote the prescription
• 行きました = the person went to the pharmacist

So the timeline is:

1. the doctor wrote the prescription
2. the person took it
3. the person went to the pharmacist

It has its own meaning. It is not just a grammatical connector.

• 持つ = to hold / carry / have with you
• 持って = holding / carrying / bringing

So 処方箋を持って really means the person physically had the prescription with them.

The て-form both:

1. keeps the meaning of 持つ
2. connects it to the next action

So this is not the same as an empty connector like and in English. It still means having/carrying.

Yes, depending on context, that is a very natural English translation.

Literally, the Japanese is closer to:

• Having the prescription the doctor wrote, (I) went to the pharmacist.

But natural English often turns that into:

• I took the prescription the doctor wrote to the pharmacist.
• I went to the pharmacist with the prescription the doctor wrote.

So if you already know the meaning, this is a good example of how Japanese and English package the same event differently.

A helpful breakdown is:

• 医者が書いた = the doctor wrote
• 処方箋 = prescription
• 医者が書いた処方箋 = the prescription the doctor wrote
• 処方箋を持って = carrying the prescription / with the prescription
• 薬剤師のところへ = to the pharmacist’s place / to the pharmacist
• 行きました = went

So the full structure is:

• [医者が書いた 処方箋] を 持って、[薬剤師のところ] へ 行きました。

That is:

• [the prescription the doctor wrote] + object marker
• holding it
• to [the pharmacist’s place]
• went

This is a very typical Japanese sentence pattern: a modified noun, then a て-form action, then the main verb.