What caused it?
Before you visit the DC, I recommend you take a minute to consider some alternatives.
I injured my neck many years ago (football) and am now looking at reconstructive surgery. I suffer from the same symptoms that you describe...and more.
The reason you are feeling pain in your neck is because one or more of the nerves branching out from the spinal column down your arm is being impinged upon by the bones in your cervical spine. Like I said...why? Did somebody drop a piano on your head?
Depending on your age, some forms of arthritis...bone spurs...can cause your symptoms. Alternatively it could be something else...but that is why you need to see a specialist.
You need to see a neurosurgeon before you see the DC...and here's why: Occasionally, some of us are born with certain congenital "problems" in our spinal column that can cause you to suffer a terrible injury if your neck is twisted or impacted in certain ways. Some folks (me included) have spinal vertebrae defects. In my case, the hole through which the spinal column central nerve travels is too small. That is, the gap between the big nerve (You know...that one that if hurt causes you to die or be paralyzed?) and the bones is too small. So small in fact that the spinal nerve is easily hit and bruised. In my case for example, after reading my MRI and X-rays, my neurosurgeon told me that if I got in an auto accident that involved "whiplash" from virtually any direction, OR if I let a DC try to "adjust" my cervical spine, I could very well be either killed outright or be a quadraplegic for the rest of my life. He also said that I'm lucky to be walking now...after four years of banging my linebacker head on other people! (No wonder I got all those "stingers"!)
Don't mess with this. See a specialist...now.