Brief Answer:
This could be a heart disease, need more information

Detailed Answer:
Hello
I share your concern
Left sided chest pain at your age is a matter of concern, this could be related to heart or chest wall disease
I would like further information to guide you better like
History of breathlessness or palpitations
any risk factor for heart disease like smoking, alcohol and family history or high cholesterol or sugar
Since how long you have this problem?

First of all you should rule out the heart problem, so you should immediately consult your doctor for examination, recording of blood pressure and investigation like EKG or serum cardiac markers if need be

Indigestion and diarrhoea can be caused by gastroenteritis or acid peptic disease due to stomach hyperacidity
You can take anti acidity medicines like pantoprazole or rabeprazole with antacids
Have lemon water and fresh fruits
Avoid fatty fried spicy and junk food or carbonated drinks
Say no to smoking and alcohol

If you can answer my questions I will help you out in best possible way
waiting for your reply
Best wishes

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Brief Answer:
Chest wall disease like costochondritis or muscle pull

Detailed Answer:
Hello
Thanks for your reply
If you have already been evaluated for heart disease than this could be chest wall disease like costochondritis or muscle pull

In my opinion you should take ibuprofen and hot fomentation for pain
Deep breathing exercises and relaxation exercises are recommended for you
Have multivitamin and calcium supplements

If it persists or worsens than book an appointment with your doctor for an X ray chest and pulmonary function test
I would advise you to quit smoking as earlier possible

Thanks and regards

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