4 year old with anxiety?

My daughter is 4 and is in her 2nd year of preschool and lately she’s been complaining about her belly hurting on the ride home from the bus stop. She will lay on the couch for a few and then be good to go and playing like normal. On the way to the bus stop she was complaining again that her belly is starting to hurt. I remember last school year she went through a phase of her belly hurting just like this but I’m not sure how to have a kid friendly talk about anxiety. Her answer is always “ it just does” when I ask why it hurts. Im sure it could also be a bug and im just overthinking but when I didn’t want to go to school and have anxiety my stomach hurts also.