Toddler neck pain

Ch

For about a week now my two year old has been complaining their "back hurts". She only mentions in when in the car seat. (To and from day care, 20 minutes). When I touch each area, it's not her back that hurts, it's her upper neck kinda where your glands are?

What could cause this? Could have have slept funny? Do I have to take her to urgent care? Hea