I havebeen able tohear fluid draining through the backof my head. Itsounds asif water isflowing down a pipe&draining through a drain. What can itbe?

Tinnitus. These symptoms may represent a condition called tinnitus, where one hears buzzing or ringing in the ears, or water noises as you have described. I would consult an ENT physician who can do tests in his office to determine whether there is eustachian tube obstruction or fluid behind the ear drum that is causing these sounds to be heard.