My 7 year old daughter, grade 2. Is having no trouble falling asleep but cannot stay asleep.?

Every night like clockwork she wakes up comes upstairs then either my husband or my self will put her back to bed. She wakes multiple times a night. To answer your question, there is no problems at home, she always gets stressed over small things. No trouble at school. She is in 2nd and doing 5th grade work. just not sure what is going on with her.