Is Either “Im Morgen” or “Am Morgen” More Correct in German?

Question

In English, I'm used to saying "in the morning," which "maps" into "Im Morgen." I don't say "on the Morning," which might translate to "am Morgen."

Z.B., I have always said, "Im Morgen gehe ich in die Arbeit." (In the morning I go to work.) I wouldn't use "Am Morgen" in this context. (Maybe someone else would.)

But in this hit song Conny (Cornelia) Froboess, a native speaker sings:

Mein Herz schlägt dabadabada
Am Morgen dabadabada
Am Abend dabadabada
Ein ganzes Leben...

That suggests that "Am Morgen" is correct in German. So would a German speaker also use "im Morgen" in this context? Or is it true, as an answerer said, "Am Morgen" is natural German, and "Im Morgen is not." Have I been using "im Morgen" wrongly up to now?

And the second verse goes:

Mein Herz schlägt dabadabada
In Liebe dabadabada
In Sorgen dabadabada
Ein Tausend Schmerzen Voll Seligkeit.

Here, the preposition "in" is used. Is that because "Liebe and "Sorgen" are abstract nouns, while "Morgen" and "Abend" are "time" nouns.

[There's a last line in the first verse I can't make out. It sounds like "Vor Freitheit und Leicht" but that doesn't make sense. Bonus for transcribing this line.]

Answer 1

"Am Morgen" is more natural German. "Im Morgen" is not natural German. Translating text does not only involve looking up the corresponding words in the other language. Grammar can differ in several aspects.

The second line means "in Freud und Leid" which is a short form of "in Freude und Leiden" meaning "in pleasure and pain".

Btw. based on the intonation I would cite like:

Mein Herz schlägt 'Dabadabada' am Morgen.
... 'Dabadabada' am Abend.
... 'Dabadabada' ein ganzes Leben lang.

So in the first line we have a complete sentence. The other lines are only text fragments.

Answer 2

"im Morgen" is a word-for-word and wrong translation of English "in the morning". In German only "am Morgen" is usual.

Answer 3

Why do you think a standard English phrase like "in the morning" should automatically translate into German word by word? There are many similarities between the two languages, but also many, many differences which, frankly, must be learned.

Same thing the other way round: As a very simple example, German speakers just have to adjust to the fact that they can't say "I go into the school" as they would say in German instead of "I go to school" if they want to speak proper English. The more akin two languages are to each other, the more difficult this might turn out to be, as there seems to be no scheme in what is different and what isn't; from English to Chinese, on the other hand, I guess you wouldn't bother to think there could be anywhere an easy translation like the one in your example.

To answer your question, "Im Morgen" isn't standard German for "in the morning". You would say "Am Morgen". However, you would say

Im Morgengrauen (= at dawn)

In der Früh (= in the early morning, which is used in the south, Bavaria and Austria)

This is mainly because "Morgengrauen" implies a duration (from the first rays of light to the appearance of the sun), whereas "Morgen" just labels a section of the day as opposed to noon or the evening. More so, "Morgen" is the time when work begins, whereas the English term often covers the first half of the day until noon. At least in the southern half of the German language area, the "Morgen" is followed by the "Vormittag" (forenoon).

Yet, it is not impossible to use the expression "Im Morgen", especially if you take it as the term for "the time tomorrow":

Im Morgen (= poetic for: in the future)

Following a hint by @Mac, I'd like to point out that in this case we're dealing with the noun "das Morgen" (tomorrow = the future). But I could as well imagine that "der Morgen" (the morning) is used with "in" in a poetic context, but to do this you should explicitly know what you're doing which is somewhat above the level of a learner.