رجعت عالبيت بكير بسبب وجع راس.

Because the verb already tells you the subject.

رجعت includes the meaning I returned / I went back in context, so Levantine usually drops أنا unless you want emphasis.

• رجعت = I went back / returned
• أنا رجعت = I went back (more emphatic)

Arabic often leaves subject pronouns out when the verb makes them clear enough.

رجعت comes from رجع, meaning to return, to go back, or to come back.

In English, the best translation depends on context:

• I went back home
• I came back home
• I returned home

Arabic رجع does not force the same come/go distinction that English does, so translators choose the most natural English wording for the situation.

It is a very common spoken contraction:

• عَ = short form of على
• البيت = the house / the home

So:

• عالبيت = على البيت in colloquial pronunciation/spelling

In Levantine, على + ال often becomes عال.

Examples:

• عالطريق = on the way / on the road
• عالجامعة = to the university / at the university depending context

In Arabic, البيت can mean both the house and home, depending on context.

In a sentence like رجعت عالبيت, it normally means I went back home, not just I returned to the house. This is very natural and idiomatic.

So even though it literally contains the house, the everyday meaning is often simply home.

Yes. بكير is a very common Levantine word meaning early.

So:

• رجعت عالبيت بكير = I went back home early

It can describe time in general:

• إجيت بكير = I came early
• فيق بكير = he wakes up early

You may see other Arabic varieties use different words more often, but بكير is extremely normal in Levantine.

Because بسبب usually introduces a noun phrase, while لأن usually introduces a full clause.

Here we have:

• بسبب وجع راس = because of a headache

That is a noun phrase, so بسبب fits very well.

If you used لأن, you would usually continue with a clause, for example:

• لأن كان عندي وجع راس = because I had a headache
• لأن راسي كان عم يوجعني = because my head was hurting

So both can express the idea of because, but the grammar after them is different.

وجع راس is a common colloquial expression meaning headache.

Literally, it is something like:

• وجع = pain
• راس = head

Together, وجع راس functions almost like a set expression: a headache.

If you say وجع راسي, that is more like my head pain or the pain in my head, which can also make sense in some contexts, but وجع راس is the standard everyday way to say a headache.

So in this sentence:

• بسبب وجع راس = because of a headache

Because Arabic does not have an indefinite article like English a / an.

So:

• وجع راس can mean a headache
• بيت can mean a house
• ولد can mean a boy

Indefiniteness is understood from context.

That is why بسبب وجع راس naturally means because of a headache, even though there is no separate word for a.

In formal Arabic, you often see رأس.

In colloquial writing, especially Levantine chat-style or informal spelling, people very often simplify it to راس.

So:

• رأس = more formal / standard spelling
• راس = very common colloquial spelling

Both point to the same word, and learners should get used to seeing these informal spellings in dialect.

A natural pronunciation could be written approximately as:

rji3et 3al-bēt bkīr bsebab waja3 rās

A few notes:

• ع is often represented as 3
• عالبيت sounds like 3al-bēt
• بكير has a long ee sound: bkīr
• راس has a long aa sound: rās

Exact pronunciation varies a bit by country and city, but this is a good general Levantine-style guide.

Not completely. Arabic word order is flexible, but this version is very natural:

• رجعت = verb
• عالبيت = place/destination
• بكير = time
• بسبب وجع راس = reason

So the sentence flows as: I went back home early because of a headache.

You may hear slight variations, but this one sounds smooth and normal in Levantine conversation.

Yes. In colloquial Arabic, وجع راس can also mean a nuisance, a hassle, or something annoying.

For example:

• هالموضوع وجع راس = this issue is a headache / a real hassle

But in your sentence, because it follows بسبب and explains why someone went home early, the literal meaning headache is the natural interpretation.