what is shakespeare messages in macbeth and romeo and juliet play?

Are you looking for a common message in the two plays?  If
so, I would start by examining the source of the tragedy in both stories.  Both plays
end in a number of deaths including those of the main characters (Romeo and Juliet,
Macbeth and Lady Macbeth).  So which flaw or flaws of the characters caused their deaths
and the deaths of so many around them?

In the case of
Macbeth, both Macbeth and his wife are done in by their ambition.  In order to get (and
keep) what they want, they'll stop at nothing including people to whom they should be
loyal (Duncan), former friends (Banquo), and even small
children.

In the case of Romeo and Juliet, the characters
are doomed by both their haste and their selfishness.  In order to get what THEY want,
they act without forethought of the consequences of their
actions.

So if you're looking for a message common to both
plays, you might say that the characters are doomed by pursuing what they want at the
cost of others' lives and happiness.