Chest tightness and shortness of breath when you sit down may be caused by respiratory diseases or heart diseases. If it is caused by heart or lung disease, you can do chest X-ray and electrocardiogram, and find abnormalities should be treated promptly.
Overwork or strenuous exercise can also cause chest tightness and shortness of breath, which can be relieved by resting for a while. It may also be caused by high blood pressure, which should be controlled promptly. If it is caused by bronchitis or bronchial asthma and other diseases, you can inhale oxygen.
It is recommended to ensure sufficient sleep, usually pay attention to the combination of work and rest, maintain a happy mood, avoid tension or excessive pressure, and participate in more sports, which helps to strengthen the resistance. Serious symptoms should be timely to the hospital for treatment.