This article by Daniel Lopez, D.O. is re-printed from the Internet -

A “knotted” spasm in the trapezius muscles is a common pain complaint. You can tell if you have one, simply by squeezing the fleshy area between your neck and your shoulder. If this area is sensitive, tight, and painful, then you have “knots” in your trapezius.

People often seek out massages, injections, medications, and more, to get rid of these painful knots. We like to blame it on stress, backpacks, and all kinds of other reasons for this pain. Unfortunately, few people ever offer solutions that actually work because they do not understand why the knots develop in the first place.

Massages and injections may not work because the reason for the spasm in the muscle is not addressed. For example, the trapezius is becoming tight and “knotted” for a reason. The reason may be, because it is responding to a slight dysfunction at the acromioclavicular joint (AC joint), which is a place where the muscle attaches and a joint the trapezius moves.

The problem is that the AC joint does not actively hurt, so it may not be in our awareness that there is a problem there and it may not be in the awareness of the massage therapist, physician, practitioner, or person giving you an injection. Therefore, the trapezius spasm gets massaged, squeezed, injected, and lots of other therapeutic interventions, but the spasm is still there. Why? Because the trapezius muscle is contracting to protect the dysfunction at the AC joint.

Unless the AC joint problem gets resolved, the trapezius will continue to spasm. The solution, therefore, is not to work on the tight trapezius “knot,” but commonly may be to work on the AC joint problem the trapezius is responding to. The trapezius attaches on the clavicle and shoulder blade. The clavicle articulates with shoulder blade at a structure called the “acromion.” Together they make the “acromioclavicular” joint.

Although not the ball and socket joint of the shoulder, the AC joint is part of the shoulder and can have an effect on shoulder range of motion. A contraction of the upper or lower trapezius can produce motion at the AC joint. Therefore, even a slight problem at this joint can produce a reflexive contraction to protect the joint from becoming more problematic. The end result is a spasm or “knot” in the trapezius. Think about what may be happening when people wear backpacks that are too heavy. The straps will put a lot of pressure on these joints and cause them to stop working properly. Then the trapezius muscles will contract and a permanent knot will be there unless the AC joint dysfunctions are resolved. Too often, specialists are looking in the wrong area.


Check out this video -

 

 
 Grab onto your trapezius between your neck and shoulder joint and give it a squeeze. Tenderness here may be indicative of an AC joint dysfunction. Also, it gives you a starting point to know how things have changed afterwards.

Find your collar bone and trace it outward until you feel the end of it. There may be a digit there or a bump. That is your AC joint. Another way of finding it, is simply to on the top of your shoulder and look for a bump.

Grip your AC joint with your thumb and index finger and slowly wiggle it back and forth. You may notice that at first it is not tender, but as you do this an underlying tenderness will show up. Do this until you feel that the bump can move a little more freely.

Recheck your trapezius and see if it feels different.

Do this once a day until it stops feeling tender and is freely moveable. You should notice your trapezius will likely feel less knotted and less sensitive.

Hopefully this will help you to understand why other treatment methods have failed to produce results. It is important to ask why a muscle is producing an active spasm or “knot” and dealing with the reason. The other option is living with the pain that this unresolved issue produces. Which sounds like the better option?