Yeah it's certainly worth trying, it could/hopefully be something that simple.
The reason I suggested it, is cause I have expereinced cracking and popping in my ears myself with the jaw moving, or if I turned my head to an angle or similar I used to get the loud cracking etc that you explained, and with me it was wax build up.
I sympathise with you suffering with tinnitus
I have no expereince with that one, but know from others how annoying and upsetting that can be..
Hope you find an answer soon