I woke up with a cold sensation in my head. like someone poured cold water on top of the left side of head that trickled down into my neck. what could potentially cause this? have had headaches, plugged ears and had a cold this last week?

It may be "occipital neuralgia", where one of the sensory nerves coming out the back of the head (at the base of the skull) gets pinched or irritated, cause a variety of symptoms. This can be caused by arthritic changes in the spine, or muscle spasms caused by stress. I would check in with your Family Doctor, or see a neurologist if it continues.

It is possible that you have a sinusitis. You can empirically start with Flonase and Zyrtec (both over the counter) but if that doesn't work then see an ENT doctor.