Thank you for your query.
is caused by irritation to the vagal nerve. This is not Only from your heart but your stomach and the lower third of your esophagus
as well. Anxiety
and tension can irritate your stomach and even cause a peptic ulcer
, This is most probably responsible for your loss of appetite and pains into your left arm and shoulder. I suggest that you need help for the anxiety and that you need an acid blocking medication as well(so called PPI). You are a very young person to be suffering from anxiety and the origins must be examined and treated. The doctor is not the only person that can help you perhaps you need to speak to the psychologist
as well. A person is not only a physical being, but a psychological and a sosio-economic being. When one is not well all three these aspects need to be addressed . Please speak to someone regarding this. I trust this information helps you. Kind regards.