Question about a weird sensation when deadlifting heavy (NOT ASKING FOR MEDICAL ADVICE):

When I deadlift (conventional) heavy, I get this weird burning sensation that isn't painful, just uncomfortable. The location is right around my waistline above my right butt cheek. I would describe it as if someone put a small hot object against my skin and held it there for a few seconds. The sensation subsides a few moments after my set is complete and I don't feel it at all when doing my lighter BBB sets. Anyone else experience this?

Additional info: The only warmup I do before deadlifting is some light reps with 135lbs and 185lbs before moving into working sets. Think that possibly some bodyweight hyperextensions may loosen me up better for my heavier sets?