I have battled tachycardia for the past couple years. I have had many heart tests which all come back normal apart from sinus tachycardia. However, in the past month, I have developed a crushing pain in my left arm and jaw. It started in the arm and eventually spread upwards. I have been to the ER a bunch of times and each time, they say it's not a heart attack. The pain is present more often than not and occurs throughout the day, worsening when I am active at all. I have also had some reflux and nausea. All symptoms of a heart attack. This pain will not go away. I feel like the doctors are missing something, that a heart attack is looming or that it's unstable angina. The doctors have taken me seriously each time I go in, but I feel like I'm living there and they have yet to give me an answer. It's so terrifying. I type this as I sit awake with crushing arm and jaw pain, frightened I will die tonight and leave my babies alone. I'm 29. What should I do?