Why does lying on my side cause sternum pain?

Generally, chest pain caused by lying on one's side during sleep may be related to physiological factors such as prolonged duration of side-sleeping, or it may be associated with pathological factors such as trauma or pleurisy. Symptomatic treatment can be provided based on the specific cause. The details are as follows:

I. Physiological Factors

Lying on one side for an extended period without timely adjustment of sleeping posture can compress the chest area. Prolonged local pressure may lead to discomfort or pain. This condition typically does not require special treatment and can be relieved simply by changing the sleeping position.

II. Pathological Factors

1. Trauma

If there is a clear history of chest trauma resulting in local soft tissue injury, pressure on the affected area while lying on one's side may also trigger pain and other symptoms. In most cases, symptoms subside with adequate rest and do not require specific medical intervention.

2. Pleurisy

Pleurisy is an inflammatory condition primarily caused by infection with pathogens such as bacteria or viruses. Main symptoms include chest tightness, chest pain, and difficulty breathing. These symptoms often worsen when lying on one's side. It is recommended to take medications such as amoxicillin capsules, levofloxacin capsules, or cefixime dispersible tablets under a doctor’s guidance to alleviate symptoms.

In addition, pneumothorax, tuberculosis, and pulmonary infections are also common contributing factors. Prompt medical evaluation at a hospital is necessary to identify the underlying cause and receive appropriate treatment.