You should read up on controlling motors from digital circuits and follow a tutorial until you understand the "gotchas".
You have to be careful with the pins on an Arduino and not trying to draw too much current from them. A motor very likely needs several times more current than an Arduino digital pin can provide (you should keep the current draw on an Arduino pin ≤20 mA. Your motor might well draw 10 times that much. You might have damaged or destroyed the pin you used.
Secondly, motors use inductive coils (electromagnets). Inductors have an effect called "back EMF" that causes a reverse surge of current when you remove power from them. That will also fry whatever solid state component is driving the inductor. (The Arduino pin if you're trying to drive the inductor directly, or a transistor if you're switching the current to the inductor using a transistor.) You need a "flyback diode" on the inductor to protect the circuit that drives it.