For the past month, or so. Iv been having strange sensations and pressure/pain in different regions of my chest. Sometimes its dull and shoots through my arm down to the inside of my elbow, or to my back between my shoulder blades. Sometimes it feels like someone is stabbing my lungs with a needle. Then i feel strange and lightheaded. When i feel my pulse at my neck, i notice my heartbeat is irregular and sometimes beats really slow and weak, then suddenly starts beating very rapidly and strong, then slows again. Sometimes, it even feels like its beating twice in one go. When this happens, i start to feel this extreme fear that i cant control. I feel like i might die, and feel so helpless. I feel really cold and i shiver like i am standing outside in the middle of winter. Sometimes my heart starts pounding like iv been running full sprint for several minutes. Iv already been to the ER once. After they gave me some kind of medicine to stop shaking, and get my blood pressure down, they just kept asking me if i had a history of anxiety and i would always answer sort of. because its more true than no. . They discharged me with nothing more than a Come back, if it happens again... . So i guess my question is this. Is what ever i am experiencing real, and dangerous? Or is this all in my head? . What would you recommend that i do? How soon?