There could possibly be a variety of medical conditions that could be causing your tinnitus. If you have ruled out all the common causes, you should have your doctor take a look at you and see if you have any other symptoms for other health conditions. Some ailments that could be a cause include: malformation of capillaries, Miniere's disease, and acoustic neuroma. If you happen to have one of these conditions, your doctor may be able to help you with them.
By making some simple adjustments you can help make the noise from tinnitus a little bit more bearable. One important thing to do is to avoid any irritants that could be causing your tinnitus. If you know loud music aggravates it, then wear ear plugs to help your ears. If you smoke, you should consider quitting since nicotine is a known irritant.