I have had ringing in my left year for 10 years now and the last 5 years it has been getting alot worse. I have been to several doctors and the last ear and nose doctor is sending me to the http://www.tinnitusclinicminnesota.com/

They seem very knowledgeable and specialize in tinnitus and want to help as the other doctors just said you will have to live with it. I think they use a combination of hearing aids and sound therapy. Going after thanksgiving for a evaluation and could let you know how it works out. But it sounds like it is not an over night cure. It is funny that several have stated it is the left ear that the ringing is a problem  but when you think about it in the old days without cabs and cabs that where very loud I spent most of the time looking to the right at the implement or beet truck I was loading and the left ear was the one that was exposed the most.