I am interested in observing the rise of the self-checkout lane. Is there a data set that shows the addresses of pharmacies (not companies, actual establishments) that have self-checkout lanes and when they got them?
I think no such dataset exists. However, there might be some roundabout ways of approximating that information.
Here's a Yelp query for reviews that feature the phrase "self checkout" in the Boston area. You can see both mapping and also the metadata that the results are "1-10 of 97" and you can select specific establishments. You can mirror this query using the Yelp API without going through a browser.
This isn't particularly comprehensive because a business needs a review that actually mentions "self-checkout" and the "self-checkout" phrase doesn't necessarily indicate that self-checkout is actually present (a review could include "gee I wish this store had self-checkout" and will come up). However it should still paint an approximate picture and would allow you to find specific locations that use self-checkout.
You can repeat this request for different geographies and if you automate it you could even cobble together your own database, or create your own tool for dynamically searching this data. Yelp has a fairly robust developer API and if you're able to accept the caveats of its information, it could be a good way to assemble a data set.