They are in your lower back and feel like you just got done doing dead lifts, atleast for me they do and yes helladrol can do that but really rare to hear it on helladrol.
I got them during my helladrol cycle. Started about week 3 lasted till I quit which was 5 weeks was running 100mg/day. They werent to bad most the time but stiff leg deadlifts could get them going pretty bad.