From Discover on Google https://www.insider.com/signs-your-workout-is-hurting-you-2018-5
During a whiplash injury the soft tissue in both the front and back of the neck can get damaged. When this happens trigger points will form in the muscles. These points will produce pain, refered pain, as well as stiffness and weakness. Trigger points in the neck muscles quite often refer pain into the head causing headaches and migraine pain. These points don’t resolve with stretching or rehabilitation exercises, they must be specifically released with a technique such as trigger point massage therapy.
The supraspinatus muscle makes up part of the rotator cuff. It is responsible for assisting in shoulder abduction as well lateral rotation and stabilizing the shoulder joint. This muscle is often overloaded in labourers and tradesman who have to do a lot of overhead work. Athletes who do a lot of throwing movements will also frequently have Tigger point in this muscle. These trigger points will cause pain to be felt into the shoulder and down the arm, as well as stiffness and weakness.