When they change the tires, most shops will balance the wheel after they mount the rubbers. Find the invoice from when you changed the tires and see if it says mounth and balance on it.

As Jani said, an unbalanced wheel would cause a vibration while driving fast (lets say 40+ mph)

Pulling left or right I think would be more closely related to the car needing an alignment rather than wheel balance. (unless it's pulling + vibrating) IMO