Where is it?
Your Trapezius, or "traps", are a pair of large triangular muscles that attaches approximately from the bottom of the skull, to the back of the shoulder, to about the mid-back. This is the big muscle that most people feel in the tops of their shoulders through the back of the neck, as well as a large part of the upper back.
What does it do?
The traps are responsible for supporting and rotating your arms, as well as allowing the shoulders to move up, down, forward and backwards. These muscles allow the shoulders to shrug and rotate and also support the neck and allow it to move.
What makes them hurt?
A large majority of people carry their stress in their shoulders - which is actually tightness in the trapsezius muscles. Stress can make them tense up, causing the shoulders to shrug and lift which pulls on other parts of the back and neck. Sitting for long periods of time with bad posture such as at a desk in front of a computer, or staring at a phone can cause strain and tightness in the traps. Additionally, lifting heavy objects or over-exercising can irritate these muscles.
How can massage help?
Since the trapezius muscles are so large and dense,, massage therapy can keep them loose and flexible, helping them to relax and drop so they don't over-pull and get strained and sore. Massage for trapezius pain may also include work on the pectoral muscles in the front of the shoulders because if the shoulders are constantly lifted and hunched forward, the pectoral muscles can also get shortened and tight, so releasing these muscles can help the traps rotate backwards and relax more easily.
This muscle can be easily worked on both laying on the massage table face up and face down, and can also be very effectively massaged in the massage chair without needing to disrobe.
What can I do besides massage to help them?
Making sure your posture is good when sitting and working, as well as taking frequent breaks during the say to move can help keep the traps from tightening up due to "computer back" or "text neck". Stretches for the shoulders, neck, and back can also help keep these big muslces loose and sitting in the right places. Simple exercises such as neck circles and shoulder circles and yoga exercises such as cat/cow can help keep pain and stiffness out of this well-and often over-used muscle group.