What Causes Popping Sound From Left Side Of Head And Towards Ear?

HI, my name is James Cofer. I am 23 years old. I most certainly believe i am suffering from some sort of brain injury. The oxygen level to my brain was at it's lowest possible point when i hit my- head. this incident occured in 2007. To my knowledge i have one previous injury to the brain. my head pops alot towards the back-let hand side of the skull, making it's way around toward the left ear. i also noticed that i listen too much out of my left ear. when i was awaken, after the incident; the left ear felt as if it were folded (inside out?).. also, sometimes its as if everything i hear is (emitted through glass?) please alleviate my concerns. also, may one order a cat scan at the local emergency room with no insurance coverage. your responce is highly appreciated. Thanks, James w. Cofer