Hi K., the exact thing happened to me with one of my twin girls right around 22-24 months. She would start crying in the middle of the night and would want us to come sit with her or take her out of the crib. Also, she didn't want to go to sleep at night without one of us sitting by her crib. We figured out pretty quick it was behavioral, not her being sick, teething, etc (we also consulted with our PED and he thought it was behavioral). I have wondered if she was scared or had a bad dream the first night it happened, and then after that she was afraid to go back to sleep if she woke up. After a few sleepless nights, we decided to let her cry it out. We would sit with her after we put her to bed, but we would not go in during the night. Oh, I will also say, she cried so hard the first couple of nights she would make herself throw up. We would just listen for a few minutes to make sure she was not going to throw up and then we let her cry. The during the night waking was eradicated within 1-2 nights and she didn't cry more than 30 minutes. For around 5-6 months she has slept well, just recently she started doing it again. Since we knew what she was doing, after the 2nd night we let her cry it out. It only lasted one more night. Needless to say, for us, ignoring the behavior has been the trick! She always has a nightlight, her favorite blanket, a couple of books etc in her bed. And she sleeps in a crib right next to her sister. So, I felt she had everything she needed to sleep well. Best of luck!!! F.
ps- I forgot to tell you that if we went in and picked her up or touched her, it made it much worse- she would then scream for us to take her out of the bed.