A sudden abrupt movement of the head and neck can be major source of neck pain and stiffness. Not being able to move your neck in a certain direction can be a big pain in the neck. You may not think its a big deal, but the simple activities of daily living can become a chore: For example, driving a car and looking at your blind spot, changing positions from seated to standing, even getting into a comfortable position for sleeping or watching tv. This is often called a sprain strain of the neck. Neck Pain, stiff neck, decrease in range of motion and muscle spasms are common symptoms. So what can you do for this if you woke up with it on Wednesday Morning?
Personally, i would recommend heat therapy. I would see a chiropractor and perhaps a massage therapist. Yes it is going to take some time, sometimes up to a few days- but it will get better. I would also recommend some type of pain relief gel, such as biofreeze. Also, i would use a supportive contoured neck pillow at night. For example: the cervical traction neck pillow or the arc4life linear gravity neck pillow are two examples.
Finally, change up what your are doing in your daily life. If you are carrying around a heavy purse, change that right away. Don't carry things on your shoulder, carry them on your side. Using a back pack or a different shoulder bag (one across the chest for example ). Also, don't fall asleep on the couch in a weird contorted position. Don't use multiple pillows at night to prop yourself up- you are setting yourself up for a stiff neck, and causing forward head posture. Finally, change up the ergonomics of your desk and workstation. Use a lumbar support at your desk and while driving for maximum comfort.