My baby age is 1 year old, today she fall down from bed to tiles floor and her head back side found pain. but head is ok no fraction or hamarage. but i notice sometimes she touch her head back side by both hands fingure. others all activities ok.

Hard to guess but: DISTANCE matters. Babies are not super fragile, which is one reason why we human haven't gone extinct yet. Regarding future head bonks (there shall be many), if a child is acting quite differently even after a mild bump, one should contact her doctor. Head bonks with a short-DISTANCE low-impact on the head, little crying, and no unusual behavior after the first hour, usually don't cause problems.