attacks characterized by upper back spasms …

Over the past year or two now I have been having sporatic incidents characterized by severe upper back cramping, sometimes making me nautious to the point of throwing up. Until two days ago, it hadn’t happened for sometime.
I used to think it was from overeating at meal time, although it may be somewhat of a trigger, I have ruled that one out.
The 1st time I ever remember having one of these painful bouts, I remember at 1st I thought it was indigestion or stomach pain, I even tried to throw up hoping to ease the pain but I couldn’t, then I wondered if I was having a heart attack?…after about 30min of agravating upper body cramping I had my friend drive me to the hospital while I writhed and squirmed in the passenger seat, I waited in the waiting room for so long, the pain subsided after sipping on a glass of water.
I had thought it was my body reacting to dehydration as I was working out at the gym in the morning, taking creatin, drinking coffee at university, and moving furniture in the afternoon and evening as a part time job. Of course I was not paying enough attention to fluid intake (not coffee).
These days I am not nearly as active, but still it happens from time to time and it is a very nasty experience. Does anyone have some feedback on this one?