Best of my knowledge says that alignment will not cause "pull", as the wheels will just center themselves toe'd in or out depending. Caster could create a pull situation so if you bring it to an alignment facility, have them check caster on both wheels.
I would imagine you have a tire issue, and that can be identified fairly easily. Check this page from TireRack -
Tire Tech Information - Diagnosing Tire Pull
if nothing else, you can eliminate some potential causes.