Dear Shiyiin, Thanks for providing quick additional information.
I understand your concern.
Such discomfort in chest, during times of sitting and lying down could be due to Costochondritis. It is an inflammation of the cartilage joining ribs to chest bone. It is this inflammation that causes the sharp chest pains inside the chest wall.
This is not a serious issue, and can be managed with medications.
Nerve can be compressed due to inflamed cartilage and thereby the pain can be felt in arm/ back too.
To treat this condition doctor advise for medications. These are-
-Non steroidal anti-inflammatory drugs like- Motrin, Naproxen ,Aleve.
, specifically tricyclic antidepressants, are very helpful.
-Muscle relaxants, are also very helpful in such cases.
I would recommend that you visit your primary doctor for evaluation and get it managed.
Please let me know how I can be of further assistance.
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