It has nothing to do with a tinnitus problem. Its called a pitch, which you can hear like, bells, or other instrumental things. If you are into the meditative, spiritual/body work, this is symptom that is not medical but spiritual. You are turning in to frequencies beyond the normal hearing range.
When you listen to music, watch television, any elevate sound, you will hear it: Oscilating frequencies. That's one form.
Another, is where you hear bells that are light pleasant. They don't happen all throughout the day (my exp), but at some moments--alone.
The spirits are trying to make contact with you. This the beginning of your ability of clairaudience. They will grow into a more comprehensible form of communication. You will hear them actually talk to you. You not their yet. Keep doing what you're doing. You are very aware of it and alert and that's all you need.