The front of chest pains: #THINKSTOKNOW The Pectoralis Major muscle group is the large, flat muscles found in the upper chest region. The muscle has four overlapping sections that attach to the ribs, collarbone, chest bone, and upper arm bone at the shoulder. This muscle group contracts as you push with your arms in front of you (e.i. the bench press) and when you rotate your arms inward towards your trunk. The Pectoralis Major can contain up to five different trigger points that refer pain in the chest, shoulder, and breast regions. Additionally, pain or numbness may radiate down the inside of the arm and into the fingers. Trigger points in this muscle group tend to activate trigger points in the upper back muscles that produce pain between the shoulder blades. The Pectoralis Major muscle group is the large, flat muscles found in the upper chest region. The muscle has four overlapping sections that attach to the ribs, collarbone, chest bone, and upper arm bone at the shoulder. This muscle group contracts as you push with your arms in front of you (e.i. the bench press) and when you rotate your arms inward towards your trunk. The Pectoralis Major can contain up to five different trigger points that refer pain in the chest, shoulder, and breast regions. Additionally, pain or numbness may radiate down the inside of the arm and into the fingers. Trigger points in this muscle group tend to activate trigger points in the upper back muscles that produce pain between the shoulder blades.