Ringing in your ears is caused by these little hairs in the inside part of your ear. These hairs bend over when there is a noise coming through the tube and are supposed to bend right back up automatically when the sound is over. Titinitus is caused from these hairs not bending back up, deaf people have this.
Heres a diagram of the ear:
What you could be experiencing is something wrong in the cochlea where the hairs are
Or fluid in the eustacion tube
HOWEVER
i am not a doctor, i just learned about this in anatomy and you should see an actual doctor because there are a lot of other more specific causes of this.