אני שומעת טוב, אבל לפעמים האוזניים שלי כואבות בגלל הרעש במשרד.

Because the speaker is female.

In Hebrew present tense, the verb form agrees with the subject’s gender and number.

• שומע = masculine singular
• שומעת = feminine singular

So a woman says אני שומעת טוב.
A man would say אני שומע טוב.

A useful extra point: in the present tense, Hebrew does not have separate forms for I, you, and she/he the way English does. The same form is used based mainly on gender and number:

• אני שומעת
• את שומעת
• היא שומעת

Because טוב here is being used like an adverb, meaning well, not like an adjective meaning good.

In אני שומעת טוב, טוב describes how she hears, so English would say well. In this use, Hebrew very often uses טוב in its basic form, even with a feminine speaker.

So:

• אני שומעת טוב = I hear well
• not I am good

You may also hear the more formal/literary adverb היטב:

• אני שומעת היטב

But טוב is extremely common and natural in everyday speech.

לפעמים means sometimes.

It is an adverb of frequency, so it tells you how often something happens. In the sentence, it modifies the second part:

• אבל לפעמים האוזניים שלי כואבות...
• but sometimes my ears hurt...

It often appears near the beginning of the clause, just like sometimes in English.

Because אוזניים is a dual form.

Hebrew has a special ending ־ַיִם / -ayim that is often used for things that naturally come in pairs, especially body parts and some other paired items.

Examples:

• עין → עיניים = eye → eyes
• אוזן → אוזניים = ear → ears
• יד → ידיים = hand → hands
• רגל → רגליים = leg/foot → legs/feet

So אוזניים is the normal way to say ears.

Even though it is historically a dual form, in modern Hebrew it behaves grammatically like a plural, so later in the sentence you get plural agreement: כואבות.

Hebrew often shows possession by putting the possessed noun first and then the possessive word after it.

So:

• האוזניים שלי = my ears
• literally something like the ears of me

This is a very common Hebrew pattern:

• הספר שלי = my book
• הבית שלי = my house
• החברים שלי = my friends

English puts my before the noun, but Hebrew often puts שלי after the noun.

Because in Hebrew, possessed nouns are often definite.

So האוזניים שלי literally includes the idea the ears of mine, which is the normal way to say my ears.

This is very natural Hebrew:

• הספר שלי
• המכונית שלי
• האוזניים שלי

Without ה־, the phrase would usually sound less natural in this kind of ordinary possession.

Because כואבות agrees with האוזניים, and האוזניים is feminine plural in agreement.

Forms of כואב in the present tense:

• כואב = masculine singular
• כואבת = feminine singular
• כואבים = masculine plural
• כואבות = feminine plural

Since אוזניים is treated as feminine plural, the correct form is:

• האוזניים שלי כואבות

Compare:

• הראש שלי כואב = my head hurts
• היד שלי כואבת = my hand hurts
• העיניים שלי כואבות = my eyes hurt

In modern Hebrew grammar, the present tense is built from forms that are historically participles, but in normal learning terms you can treat כואבות here as the present-tense verb form meaning hurt / are hurting.

So for a learner, the important thing is:

• it functions as the present-tense predicate
• it agrees in gender and number with the subject

That is why:

• האוזניים שלי כואבות works the same way, structurally, as
• הילדות שומעות
• הדלתות פתוחות in a descriptive sentence

בגלל means because of, and it is followed by a noun phrase:

• בגלל הרעש = because of the noise

That fits this sentence perfectly, because the cause is a thing, not a full clause.

Use:

• בגלל + noun
• כי + clause

Examples:

• האוזניים שלי כואבות בגלל הרעש = my ears hurt because of the noise
• האוזניים שלי כואבות כי יש רעש במשרד = my ears hurt because there is noise in the office

So בגלל is the natural choice in your sentence.

הרעש means the noise, so it sounds like a specific, identifiable noise: the noise in that office situation.

Hebrew often uses the definite article when the speaker has a specific thing in mind:

• בגלל הרעש במשרד = because of the noise in the office

If you said בגלל רעש במשרד, that would sound more like because of noise in an office / because of office noise in a more general sense.

Both can be possible in the right context, but הרעש is very natural when talking about a specific office environment.

Because Hebrew prepositions often attach directly to the noun.

Here:

• ב־ = in
• משרד = office

So:

• במשרד = in an office / in the office

In this sentence, it is specifically במשרד with the meaning in the office. This form can also reflect contraction of:

• ב + ה + משרד which becomes
• במשרד

This kind of contraction is very common:

• בבית = in the house / at home
• בספר = in the book
• בשולחן = on the table

אני שומעת טוב is very natural and common in everyday spoken Hebrew.

A more formal or written-style version would be:

• אני שומעת היטב

Both are correct:

• טוב = common, conversational
• היטב = more formal, polished, sometimes more literary

So if you are learning everyday Hebrew, שומעת טוב is absolutely worth knowing.