hi...do you suspect parasites at all? i don't know if this is part of your problem or what's causing this reaction to castor oil packs..but, i've had something similiar.
with me, i know absolutely it's parasites as i feel them (apart from other things). when i used to do castor oil packs, after about 20 minutes i'd get a surge of anxiety, sometimes difficulty breathing, usually a panic attack as well. as i got better, these reactions didn't happen.
just a thought anyhow. i don't know if it has anything to do with why it's happening for you, but i had adrenal issues due to parasites.