It seems like you are having your nerve
that comes out of the spinalcord being impinged in the area where your neck do not align properly.
The sensation of coldness is due to such pressure on nerves and the brain will interpret it as different sensation in your case its coldness
I recommend you to visit near by neurologist
to have it checked.
They may need MRI
/ CT SCAN
of spine to see whats going on and where is real compression of nerve.
mean while heat pad will help to have some relief.
Dr. JAY PATEL