What Causes Frequent Vomiting After Taking Flu Shot?

I have permanant nerve damage and spondilosis, osteoporosis, osteoathritis. disk changes. I have been suffering chronic pain for many years now. I had my adrenal glands removed in 2006 due to Cushing s disease. Now on steriods for life. I had a flu shot last friday among other problems and went into an adernal crisis, was hospitalized and had a vomiting episode, every since my back pain got much worse, pain a 9 out of 10. On pain meds it is a 7. Everysince the pain got worse I started getting tremors, my head starts shaking when I turn it to either side and when I smile my mouth and jaw tremors. I also get intermintant shaking. Could this be caused by my back injury from vomiting? or may be the flu shot?