What Causes Hearing Loss, Ringing In Ear And Headache?

Hearing loss in my right ear. Went to an audiologist and she refered me to an ENT. She said I have uneven pressure in my ear. The ringing is very loud and the hearing test was hard to take because of the ringing and I could hear my pulse like a bass drum when the ear buds were in. My right side of my head feels very weird. What could be causing this? I have some pain but nothing compares to ear infections I've had in the past. What should I expect at the ENT appointment?