Negative stress test still having chest pain

I have been having chest pain off and on for awhile now. Last week I had real bad pain in my left chest with pain the traveled down my left arm and up into my neck. I did not run to the doctor or the ER at that time because I have had pain before. Call my doctors office the next day and was advise to go to urgent care. My EKG was negative but they set me up to see a cardio doc. Before I got to my appt with the cardio I had another episode of bad chest pain so went to the ER. All my bllod work and ekgs were negative. I was there for 8 hours and had repeat test. Went and had a stress test the next day and that was negative also. I am still having chest pain on and off. Does anyone have any idea what could be going on? The pain at its worst is very scary, I get short of breath, dizzy and nauseas, with the pain on my left side chest area into my left arm, shoulder and neck. Any help would be apprciated.