Daughters in Shakespeare's time, and throughout most of history, were subject to their fathers socially and legally. Young girls did not have the pleasure of choosing to whom they would be married because that was usually a business agreement between gentlemen. Many young girls were married to older gentlemen, just like Paris is older than Juliet. But this is only part of the pain inflicted upon young Juliet. The most painful events for Juliet is when her father threatens to cast her out of his family if she doesn't marry Paris, Tybalt's death and Romeo's banishment.
First, Juliet gets caught in a paradox because she married Romeo just as her father makes the arrangements for her to marry Paris. She does her best to hold her father off as best she can because if she marries Paris, she will be committing an even greater sin by having married two men. Juliet is a good girl and doesn't want to offend God or her vows to Romeo by marrying another man, so this is a painful situation. But to add salt to the wound, her father threatens her as in the following lines:
"Hang thee, young baggage, disobedient wretch!
I tell thee what: get thee to the church o'Thursday,
Or never after look me in the face.
Speak not, reply not, do not answer me" (III.v.160-163).
Another event that greatly burdens Juliet is the fact that Romeo kills her cousin Tybalt and she doesn't know exactly why. She must choose to stay loyal to her husband and forgive him, or hate him for Tybalt's death. Juliet expresses her grief as follows:
"O, break, my heart, poor bankrupt, break at once!
To prison, eyes; ne'er look on liberty.
Vile earth, to earth resign; end motion here,
And thou and Romeo press one heavy bier!" (III.ii.57-60).
Clearly, Juliet exclaims that her heart is broken upon the news about Romeo and Tybalt.
One last example of Juliet's pain and suffering is expressed when she is letting the news of Romeo's banishment sink in as shown below:
"All slain, all dead. 'Romeo is banished'--
There is no end, no limit, measure, bound,
In that word's death. No words can that woe sound"
The poor girl just can't get a break from the vicissitudes of life all thrown at her within three days time.