Air Hunger, Dizzy, Lightheadedness, Tingling Toes, Fingers, Radiating Pain Under Left Collarbone. Xanax Ineffective. Advise?

Hi, a week and a half ago I went to the doctor because I had shortness of breath, and I felt like an elephant was sitting on my chest, and felt like I was drowning when I layed down. I was started on prednisone, Flovent, and givin azethromiacin on top of the albuteral inhaler, singulair and Zyrtec my doctor already had me on for asthma and hay fever.
Yesterday I went back to the ER because I was having extremely bad air hunger, I was dizzy and light headed, my fingers and toes where starting to tingle and the pressure on my chest was worse and accompanied by a raidiating pain that started under my left collarbone down to under my left breast. The ER took blood and chest X-ray's that where normal and sent me home with a prescription for Xanax to help calm me down during an attack, threw out the night my left sided chest pain has gotten worse along with the pressure, and I have had no relieve using the Xanax, and I almost pass out every time I stand up. I've also had swelling in my hands and ankles when I work for the past few months.
I'm worried about this pain and if I should go back into the ER today?