I hurt my back 4 weeks ago doing yard work. 2 days later I was at work and twisted a certain way and I felt a tingling in my right thigh. My outer thigh has been slightly numb since that day. It does appear to be getting better, but still has some numbness. Yesterday, my barber noticed I had developed a bald spot on the back of my head behind my right ear. He called it Alopecia Areata. Could this be caused from my back injury?

Summarized question: Does back injury cause alopecia areata?