What Causes Pain in the Pectoral Muscles?

The pectorals are four muscles that lie paired on either side of your chest. Pectoral muscle pain can arise from several causes, limiting arm movements and reducing function. It is necessary to differentiate chest pain caused by pectoral muscles from other causes of chest pain. 

Pectoral muscle pain causes have different levels of severity. Some conditions do well with rest and ice packs, but some require complex surgery and expert physical therapy.

There are two pectoral muscles in each pair. The larger is called the pectoralis major. The smaller is the pectoralis minor. These muscles lie on the front of the chest. 

The pectoralis major is much larger.  It originates at the clavicle (collar bone), the sternum (breast bone), and ribs. It attaches to the humerus, the large bone in your arm. This muscle helps in several movements of the shoulder. 

The pectoralis minor is a smaller muscle lying under the pectoralis major. It originates from the ribs and attaches to the scapula (shoulder bone). It stabilizes the scapula during movements of the arm.

Most pectoral muscle pain is caused by injury, usually due to weight exercises. The bench press is most often associated with such injury. The pain occurs at the attachment of the muscle to the humerus and the front of the armpit.

A severe injury can cause the pectoralis muscle to tear. The muscle may tear loose from the collar bone and ribs or the attachment to the arm. Tears may be partial or complete and are often intensely painful. They're classified into:

• Contusion (bruising) or sprain.
• Partial tear
• Complete rupture

A direct injury can also cause pectoral muscle pain. Falls onto the chest, heavy objects falling on the chest, or contact sports like rugby and American football can injure the pectoralis muscles. Most often, such injuries happen during the use of free weights. You will usually remember the injury that started your pain. 

The pectoralis minor lies deep under the pectoralis major. It is not injured by direct injury but by overuse. You're likely to have pectoralis minor pain if you participate in weight training, rugby, swimming, or bodybuilding. The pain from this muscle is usually subacute (the onset is gradual, and you can't exactly remember when it started). You can often date the pain to roughly when you stepped up exercise or intensity playing a sport. The pain can be severe enough to prevent your sports activity.

A complete tear of the muscle is called a rupture. Ruptures can happen at two sites, the musculotendinous junction or the tendon's insertion into the bone. The musculotendinous junction is the area where the belly of the muscle joins the fibrous tendon.

The common activities associated with such rupture are weightlifting, boxing, windsurfing, and jiu-jitsu. Pectoral muscle rupture usually affects the pectoralis major. The pain is sudden and sharp, and you won't be able to continue the activity. Since the muscle has torn loose from the humerus, it will bunch up on your chest. You will notice it as a swelling.

Pain in the chest is not always because of pectoral or other muscle problems. Watch out for:

• Difficulty breathing
• Cold sweats
• Dizziness
• Nausea or vomiting
• Fever

If you have some of these symptoms along with chest pain, you might have a lung or heart disorder. You should talk to your doctor or go to an emergency room immediately.

On the other hand, pectoral muscle pain is associated with swelling over some part of the muscle, loss of some arm movements, and visible bruising. Touching or pressing the area increases the pain.

Most strains and partial tears of the pectoralis major are managed by conservative treatment. Your medical team will put the affected arm in a sling to rest the muscle. Ice packs and pain medicines help ease the discomfort. It takes 4-6 weeks for the muscle to heal. However, in athletes and others participating in competitive sport, surgical treatment is a better option to restore the best possible function. 

Your doctor can often diagnose pectoral muscle tears based on your activity when the pain started. The pectoral muscle tear or rupture can be confirmed by ultrasound examination. But, if you decide on surgical repair, your surgeon will want a magnetic resonance imaging (MRI) scan to get a detailed understanding of the extent of your injury.

Doctors also prescribe reducing whatever activity has triggered pectoralis minor strains combined with rest and pain medicines. If your pain is more severe, your doctor will inject a mixture of a local anesthetic and a corticosteroid into the pectoralis minor tendon. They will use ultrasound to guide the precise placement of the injection.

Strength and resistance training is very popular as a fitness activity. Muscle injuries are a common accompaniment if proper warm-ups, technique, and equipment handling are not followed. Free weights are associated with two-thirds of direct injuries. Resistance machines are a safer option.