I believe the theme of the story is ocean, which is used multiple times in the poem and represents how things can change rapidly, just like the ocean.
Symbolism
The story many a time states that they were in the kingdom by the sea. This probably wouldn't have been a literal kingdom, however, and was probably a town, but was exaggerated to be a kingdom.
Imagery
The speaker is an obsessive boy who was in love with Annabel Lee. He grieved after her death and blamed things to make him seem right.
Repetition
SEA, ANNABEL, LEE, ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The ocean, in the poem symbolizes fast change, such as Annabel Lee getting sick. The angels probably symbolize the speaker's grief and blame, as well as Annabel Lee's cold.
Some examples of imagery throughout the poem are chilling which invokes you to feel the wind chilling you and as they mention the sea several times, it invokes you to hear the ocean and smell the ocean.
The story repeats many words multiple times, such as chilling, sea, Annabel, Lee and Me.