I am expereincing soreness on my left side of neck, and arm all the way to my wrist. I have not done any excercise to cause this.?

Pinched nerve. The most likely cause is something (a disk or bone spur) putting pressure on a nerve as it exits the spine. You do not have to "do" anything for this to happen. A remote possibility for left-sided arm pain is heart-pain and i would recommend you see your doctor about these symptoms.
Many possibilities. What you have is likely musculoskeletal, but there can be many reasons. It may be that you just slept in an odd position and have a vertebrae or rib "out of place." this, or other similar things - thoracic outlet syndrome, brachial plexopathy, etc, can cause nerve irritation that can affect you all the way down the arm. Try massage or stretches with ice/heat or visit an osteopath or chiropractor.