Injury to the ligamentous and muscular structures of the neck and shoulder can be caused by sudden acceleration or deceleration, as in a car accident. The tendons connect the muscles to the bones. With strain, the tendons can become swollen and cause pain. All pain seems sharp, but pain can also be described as dull, burning, crampy, shocklike, or stabbing. The description of each symptom is important to your doctor because the type of pain can help your doctor find the cause.
Weakness can be due to severe pain from muscle or bone movement.
The nerves connecting to the muscles, however, also could be injured. If the nerves are pinched, bruised, or cut, you may not be able to feel things normally. A cool arm or hand suggests that the arteries, veins, or both have been injured or blocked. This may mean that not enough blood is getting into the arm. Redness can indicate infection or inflammation.