My 7 month old fell backwards and hit the back of his head kinda hard. he cried but quickly settled down. he seems normal, but will he be ok?

Probably : Most kids who fall back from their sitting height do not generate the kind of force needed to hurt them.This would be different if they hit the corner of furnature or brickwork.They cry, and settle quiickly.I would be worried if the kid passed out at the time of the fall or developed repeated episodes of vomiting.Keep him on his normal nap/sleep schedule and monitor as needed.