Hi there ~
, shoulder and chest pain
with a normal chest x-ray are all symptoms of panic attack
. All the other symptoms that you describe classically fit into the diagnosis of panic attacks and probably a full blown panic disorder. It is a form of anxiety
disorder and since you mention there are no triggers, medications are the best way to deal with such conditions. I would rule out any cardiac problems like yourself and visit with a psychiatrist
who can prescribe the right kind of medication both pharmacologically as well as therapeutically. I wish you all the very best in you path to recovery.
Take care and have a lovely day !