Pressure in chest? Gets worse when I eat?

For the last four days I have had this pressure in my upper chest and down my sternum between my breasts. Its not as bad if I sit down and rest but when I get up to walk or do anything I get winded easily and like I need to take in deep breaths. When I eat anything it gets worse it almost feels like the food is clogged in my chest almost like a squeezing feeling and I can feel it in my throat. I went to the er because I was worried and they did ekg chest xray and blood work for heart enzymes and for blood clots and everthing was normal, my oxygen level was at 100 percent. Ie also had a little bit of a dry cough. I do have gerd but have been taking pepcid ac, the er doctor perscribed me priolsec. ive had chest heavyness before and they always say it gerd, but ive never had this pressure feeling before and not lasting for as long as it has, can gerd do this. its scary feeling almost, i dont feel any burning or anything. i dont know, just wish i knew what it was its really worrying me and making my anxiety level go up. any answers are appreciated.