strange. I don't get cramps. maybe there is something in the brand you are taking that makes it incompatible for you. Also, you might be better with ACV in water. Maybe the orange juice is working at odds with the vinegar? Just a thought.
My son loves it straight in water. But we take Eden. Have you tried making pineapple vinegar/
It is delicious, and has all the goodness of the parent vinegar.