I just walked into an Independent pharmacy and told the owner I was applying to pharmacy school, had my tech license and would like to volunteer. And he said sure, all women techs there I think he was happy to have a guy to talk to, he ended up writing me a recommendation. Independent pharmacy is the way to go, I had a lot more time to talk to the pharmacist and get his perspective on the profession. Like the above poster said, go to the little guys and tell them why you want to volunteer.
Big chains are busy and often just do not have the time to have a volunteer in the pharmacy and there is always the risk of theft.