That swishing fluid like feeling you are feeling with moving your head could definitely be fluid in your ear. People who have this condition often describe symptoms just like the ones you have.
The ear is divided into an out ear canal and the inner middle ear by the ear drum. The fluid that you are experience collects behind the ear drum, which is why nothing comes out of your ear canal when you move your head. Commonly, this fluid collects behind the ear drum because of something called eustachian tube dysfunction. The eustachian tubes run from the middle ear to the throat and they are supposed to drain any fluid that collects in the ear. However, sometimes they get swollen shut, usually because of a cold or throat infection.
Most of the time, the fluid will eventually drain as the swelling goes down, although this can sometimes take weeks. There is no real effective treatment for making the drainage occur quicker. However, if you are having significant impairment of your hearing or a lot of pain or discomfort, then you may want to talk to a doctors
">doctor about it; in particular, ENT doctors often deal with the more complicated cases of eustachian tube dysfunction.