One of the reasons store pharmacies are able to distribute the Pfizer vaccine is because the company came back and changed the storage model. In mid-May this report was issued:

FDA In Brief: FDA Authorizes Longer Time for Refrigerator Storage of Thawed Pfizer-BioNTech COVID-19 Vaccine Prior to Dilution, Making Vaccine More Widely Available

Making COVID-19 vaccines widely available is key to getting people vaccinated and bringing the pandemic to an end. Pfizer Inc. submitted data to the FDA to support storage of undiluted, thawed vials of its COVID-19 vaccine for up to one month at refrigerator temperatures. This change should make this vaccine more widely available to the American public by facilitating the ability of vaccine providers, such as community doctors’ offices, to receive, store and administer the vaccine.

Additional Information
Based on a review of recent data submitted by Pfizer Inc. today, the U.S. Food and Drug Administration is authorizing undiluted, thawed Pfizer-BioNTech COVID-19 Vaccine vials to be stored in the refrigerator at 2°C to 8°C (35°F to 46°F) for up to 1 month. Previously, thawed, undiluted vaccine vials could be stored in the refrigerator for up to 5 days.

Pfizer Inc. submitted data to the FDA to demonstrate that undiluted, thawed vials of its COVID-19 vaccine are stable at refrigerator temperatures for up to 1 month.