Hi, I Had An Abnormal Ecg Twice Yesterday, It Shows

Hi, I had an abnormal ecg twice yesterday, it shows consider inferior ischemia and anteriolateral ischemia? I was given nitro spray and it helped somewhat...am going for a stress test in 3 days. I've had Severe SVT in 2013 not many incidents after that couldn't be controlled. I went to Drs yesterday as I've had severe muscle pain in front left pec muscle,shoulder pain and a sense of being tight like a band around my chest also was a little short of breath a few times. I was kept at hospital and discharged after about 8 hrs with unconfirmed heart problems. Over the past few months I've noticed palpitations and have had very high by for me ..eg 167/96 and my normal bp is about 100-120/70-80 any ideas?