My jalapeņo experiences are widely varied - but never more than 15 minutes or so of noticeable burn. There's a
killer grilled chicken place that includes grilled jalapenos on the side. Generally they are petty mild (I eats them with seeds raw/grilled/stewed/whatever) but have encountered a few that feel like habanero scoville levels. Never experienced any burning to skin but +1 to avoid eyes and privates.
I'd say it's related to your back.