What Causes Pulsating Sound In The Ear?

I have pulsating sound in my left ear for 2 months now. I seen a ENT, he gave me a hearing test and I lost some hearing in my left ear, He almost send me for a mri with a dye contrast and that came good. My family doctor took blood before the mri and found high calcuim count so I took another one and I am waiting for the results meanwhile this hissing sound is driving me crazy. What can this be coming from?