Are my iPhone functions or screen affected?

There is no such thing as "normally dropped" with small electronics.

You can't escape gravity so when the iPhone comes to a sudden stop it does affect the parts of the phone. If you are lucky it does not break anything and your phone is still usable.

They are affected.

That is not a thing, it is well built and should withstand a moderate drop so long as it doesn't strike a hard surface at a bad angle and break the glass.