Finished 5d zpack for ear infection feel ringing in ear, fluid and a little pain and loss of hearing. could the infection still be there?

Possible: As it can still be a viral infection, very difficult to tell from the outset, also you may have chronic serous otitis media, meaning persistent fluid in your middle ear mainly due to Eustachian tube dysfunction, more common in kids though, also chronic inflammation of nasal cavity/ throat for whatever reason like allergies can cause this. Kindly revisit your doctor or ENT specialist, good luck