What Causes Acute Nerve Pain On The Legs And Back?

I have had tingley, nerve pain down my leg, back spasm, and acute left leg cramp which I had to be taken to the hospital via 911, after laying at home for 4 hours with this cramp and another 2-3 hours in the ER. in 2009. Reference 1970-1971 Vietnam, Chu Lia to Quang Tri.