During the past few months I have had some strange experiences as far as hearing sounds. One night, before falling asleep I felt a lot of pressure building up in my ears, then my ears popped and I heard the sound of many voices not audible to regular hearing. They were not talking directly to me though and it lasted only for a few seconds. The same thing happened a few weeks ago, but this time I heard a woman's voice, saying "I'm fine" and then the pressure in the ears when the message ended.

And today...well, my husband tried a dog whistle on my neighbour's dog, and I could hear sounds from 16000 hz up to 60000 hz, and they were extremely annoying to me.  Well, these are ultrasounds and nobody heard them besides me and the dog.

Could this be a sign of developing clairaudience?

Things like this happen when other signs and symptoms are also happening.  The first step is to take charge.  To do that you need to be practicing with meditation to open and close as well as attune with your own particular spirit guide.  When things start to open is when we are being told there is a higher plan for our lives and we need to listen.