I assume you mean HKG (Hong Kong) not HKK (Hokitika).
If you have *G status (or RCC paid membership) then you can use SQ lounge (near the gates they use) or TG and UA lounges at the other end of the terminal. All 3 lounges have showers. If you don't have *G status then no lounge access flying departing flight in economy.
SQ lounge is worst of the three, TG is best.