Different angles exist that you can explore in your essay on Macbeth's conflict in Shakespeare's tragedy. 

• Internal and external.  Macbeth faces internal conflict early in the play.  He doesn't want to kill Duncan because Duncan has been a fair and honorable king, and he knows it would be wrong.  He also knows he is dominated by his out-of-control ambition.  External conflict interferes with his internal thoughts, however, when his wife attempts to talk him into the assassination.  Macbeth's internal conflict withers throughout the rest of the play once he's committed treachery.
• External conflict, for Macbeth, appears first in the character of his wife, as mentioned.  Conflicts with Banquo, Malcolm, and Macduff ensue.  By the close of the play, Macbeth is in external conflict with virtually everyone in Scotland.  Even his own soldiers betray him.
• Fate also plays a role in the conflict.  If the witches know the future, do they control the future?  Is Macbeth doomed from the start?  Is hubris (attempting to rise above his station in life) really what's in play here, and Macbeth fails because he is in conflict with fate, and no one can defeat fate? 

These are three of the specific angles relating to conflict you can use in your essay.  You could also, by the way, explore the dialogue, imagery, or theme, and how they contribute to the presentation of the conflict.