Suggest Remedy For Painful Chest With Difficult Breathing

So my chest gets this feeling that someone has punched me in the heart and its painful and knocks me out of breath. I am twenty now and its been happening over the last ten or so years. I'm getting so tired of it because it used to happen once and with months in between. the last couple of years have been rough with them hurting more and happening more often. I have had ekg and a. stress test and they say nothing is wrong today it did it over and over for two hours. I used an inhaler. but it didn't help. and I no longer have insurance but idk. if I should worry but it hurts.