ENT/otolaryngologist. Any person with ringing in the ears, also known as tinnitus, should have an audiogram (hearing test) and see an otolaryngologist (ent). Some clinics or hospitals have a special expertise in managing tinnitus, so it is good to do some research about what local experts there may be in your area.
Depends. Start with your primary care doctor. Sometimes it is as simple as a build up of earwax, and removing the wax solves the problem! Ear infections, thyroid problems, injuries, and other things can also be identified by your pcp. If your pcp cannot identify the source, they will likely refer to an ENT or neurologist, depending on symptoms and exam.
Otolaryngologist. Otolaryngology is the specialty focusing on problems of the ear, nose and throat. Hearing loss, ringing in the ear (or tinnitus) and other disorders of the ear can be thoroughly evaluated and management outlined by a physician practicing in this specialty.