I'm 26 Male Just Got Out Of Hospital Because I

I'm 26 male just got out of hospital because I syncope . They did a couple test I was in for 4 days . They said all the test was good . While I was in the e.r my heart rate went from 80 all the way down to 37 and I felt like I was going to faint . I'm at ho,e and my b p is 137 over 80 and after 5 min was 120 over 90 should I be concerned ntheynmissed anything ? I also noticed I get a sharp quick pain on left side in the middle of my back