This could be several things related to a form of a condition called tinnitus, which is sounds or sensations in the ear caused by injury, inflammation, or irritation of the auditory cells in your ear. Most people experience it as a ringing, but clicking or fluttering tinnitus could be caused by spasms of the tensor tympani muscle in your ear, or from the pulsation of tiny blood vessels. A minor infection or inflammation, irritation from loud noise, fluid in the middle ear, a small hole in the ear drum, a buildup of wax, or even more serious conditions like Menière's disease or a tumor can be the cause (though this is less likely in your case).
Another possibility is eustachian tube dysfunction, which is a tube that runs from the ear drum to the back of the throat. This tube opens and closes to regulate the air pressure, and when it's inflammed or irritated, it has trouble opening and closing, and may result in a popping, clicking, or fluttering sensation. This can be brought on by infection, or allergies, or even a cold.
Most likely, this will probably go away on its own in time, but if it doesn't or gets worse or becomes accompanied by other symptoms, you will need to see your doctor or an ENT physician to determine the exact cause. In many causes a good ear cleaning will help (and this should be done by a physician, not q-tips, which can push wax further into the ear and cause the problem to be worse).
I hope this helps!