What Causes Tightness And Pain In And Around The Chest?

hi i have a problem concerning my heart and was woundering if you would be able to help
a few years ago i started to have pains in my chest and a squeesing sensation around my heart it doesnt happen all the time just really when i get stressed on monday i had the same syptoms but when i went to the hospital as usual they found nothing in my bloods, while i was in the ambulance the paramedic who treaded me adviced me to ask for a test for cardiac sydrome x but the doctor said it wasnt nessasary even tho id been the same hospital with the same symptoms 12 times before can you advice me on what my next step to get these test would be