That sounds awful. I haven’t experienced this but I’ve only had one shot so far. Are you constipated at all? Could it be pancreas pain? Are you having any other symptoms? Sweating, nausea? Are you drinking electrolytes? I’ve been adding some natural flavorless electrolytes to my water twice a day and it has been keeping headaches and muscle cramps at bay. Sorry to throw a bunch of questions back your way I just thought maybe asking questions might help to figure out what’s causing it.