Poems written by Poets can be considered as "Songs".?.
They can be. In fact, there's a whole list that can be found on Wikipedia:
https://en.wikipedia.org/wiki/List_of_songs_based_on_poems Bob Dylan is famous for this, I think.
I Feel Poems are songs having a shorter duration.
Poems can be short, they can be long, there's no set criteria. For example, the tanka (which means “short poem”) is a Japanese form that is
five lines. The first and third lines have five syllables (in the English version of the form) and the other lines have seven syllables each.
Songs themselves have to be rhythmic. As well, poetry flows just the same. Rhythm is what makes music as well as poetry. However, songs are often bad poems. According to
this article, one your take the music away, all you're left with are
lumpy syllables, cheesy rhymes, exhausted cliches and mixed metaphors. Therefore, they are related, but not the same.
Are there Hollywood movies & English plays where there are "Poems". ?
You mean a poem is recited in the movie, or the entire plot is based on a poem?