Flying ANC-SFO-BNA in August. Would really love to grab a shower during my layover in SFO. Flying on Y ticket so from what I can find I have zero access to any paid or unpaid shower/lounge options without going outside security to Freshen up lounge. I do have priority pass but not real helpful in my opinion.

Are there any other options? If I do leave security temporarily, it does not affect my checked luggage in any way does it?

Thanks