how do I access Pass files when logged into my user's shell from another user's session?

I just migrated from keepassxc to the linux pass password utility. But I often find myself **su**'ing to my user's account from another user's session, and when I try to run any pass commands on entries in my store, I get a "no secret key" error, which seems odd to me because I would think when one logs into their shell account that everything associated with that user would be available at the cli. So how then can I **su** into my user's account from another's user's session in a way that I can access my gpg keys and manage my pass files?