Q.Planted a River Birch Tree 7 feet about 5 days ago; leaves are turning yellow and curling up some.
Watering it as we were informed to do; it is in the sun. Do you think this could be just shock from transporting it? It was professionally planted by a local landscaping business.

It sounds like transplant shock or water deficit. It may recover but it may not.
I recommend that you contact the landscaping business who planted the tree and report what you have told us, right away before a week passes. If you have in fact been watering as directed, then you may have some recourse for a replacement if the tree dies. Most services will guarantee for at least a month if you have followed directions.
https://www.gardeningknowhow.com/ornamental/trees/tgen/watering-newly-planted-tree.htm