Hi, MP!
You have gotten some good advice here. I agree that it may be bathroom issues or night terrors- those are darn scary to little ones!! My little grandson used to wake up and cry the most heartbreaking sobs in the middle of the night. Finally, I noticed that whenever he had a night like that, he always woke up soaked. Sure enough, started taking him to the bathroom and the crying stopped. I don't think he ever really woke up, just went to the bathroom and back to bed with our assistance. It seems he couldn't wake up quite enough to know what was waking him. Sometimes he even said "thank you" when we took him back to bed. In a short time, he could go all night without needing to go to the bathroom, and all was solved.
Also, the same grandson has always had leg cramps at night. No doctor has ever discovered why, and he is 7 now. If she doesn't need to go to the bathroom, try gently rubbing her legs and comforting her; maybe it will help.
One other common thing is bad dreams. For that, you need to comfort her and make her feel safe, then tell her you are going back to bed but will be right there if she needs you.
Please try these things before you make her "cry it out." She needs to know you are there for her. Growing up can be scary.
Best wishes!
Blessings.