Thanks for your question on Health Care Magic.
I can understand your concern.
Possibility of stress related symptoms is more.
But better to rule out heart diseases because of left sided chest complaints.
So get done ecg and 2d echo.
If both are normal then no need to worry for heart diseases.
Stress related gastritis can cause
chest pain, nausea,
chest tightness, pressure etc.
So
consult psychiatrist and get done
counselling sessions. Try to identify stressor in her life and start working on its solution.
She may need anxiolytic drugs too.
Ask her to avoid stress and tension.
For gastritis, give
proton pump inhibitors and prokinetic drugs.
Don't worry, she will be alright.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.