One of the biggest mistakes beginning screenwriters make is to include too much backstory in their screenplays. In an effort to describe EVERYTHING about the main character, beginning screenwriters attempt to create a novel out of their script, overusing flashback sequences. But this only SLOWS the story down. By the time you've finished with the interruption to the main story you've created with the flashback, the audience can't even remember what the main story was. Plus, you may have even diluted some very dramatic sequence, which would keep your audience much more glued to your story than some long-winded backstory description.
Like with acting, screenwriters must know inherently -- back to front -- what their main character's personal history is. But the audience doesn't have to.
A good script is about the most important moment in the main character's life -- not about every moment. A lot of information can also be conveyed through images: a photo in the background of the shot that shows the main character surrounded by their family -- which shows that the main character is a family person, or maybe that their connection to a family, which is otherwise important to them, is lacking at the moment and might be what the main character needs to recover throughout the course of the film.
If you do need to use some exposition to get across some backstory, try doing so in an action sequence. Have the main character actually DOING something that conveys some other kind of relationship or even a super-power that the main character might have. While she is performing this act, she could be discussing some backstory. For example, the main character could be sword-fighting with a love interest while expressing some of her backstory -- who her parents are, etc. This then shows the audience that she is not only good at sword-fighting (which can be a weird talent to have), but it might even convey a deeper theme for the film: we often fight with the people we love the most. All the way you are getting across at least a little exposition about backstory.
Some screenwriting experts even advise writers to write what you think is your first act, then toss it. You might just find that you can just jump right into the action of the story (e.g. what you thought was the second act now becomes the first). This will prove much more interesting and dynamic to the viewer.