From Discover on Google https://www.insider.com/signs-your-workout-is-hurting-you-2018-5
Pain
Whiplash and soft tissue.
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.
Treating neck and shoulder pain.
Pain from trigger points in the supraspinatus muscle.
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.
How to treat neck pain
Strength Training and Pain Rehabilitation
Feel better with massage therapy!!
The best hand and finger stretches for pain relief | Well+Good
Neck pain and the trapezius muscle.
The Trapezius muscle is a large diamond shaped muscle located in the back and neck. It is responsible for for a number of shoulder and neck movements and helps maintain proper posture. This muscle is probably the most common muscle that I work on in the clinic. It is frequently strained and develops trigger points easily. The trigger points in the upper portion of this muscle are the most common to be found in the body. Trigger points will refer pain into the upper back, neck, shoulder, and even into the head and temple causing headaches. Chronic trigger points in this muscle are also a frequent cause of a stiff neck.
Trigger point pain and the Teres Major muscle.
The Teres major muscle is located at the back of the armpit. It originates on the posterior aspect of the inferior angle of the scapula, and inserts and inserts on the medial lip of the intertubercular sulcus of the humerus. It’s main function is to assist adduction, internal rotation, and extension of the arm. This muscle only becomes active when there is resistance added to these movements. Trigger point pain from this muscle will cause pain to be felt deep into the posterior shoulder and down the back of the arm. 
Aberdeen Chiropractic 