The connection between nerve pain in the arm and a neck injury is not always apparent. Neck injuries don't cause symptoms right away, it can take months.
For example, I have a hernia in my neck. It was diagnosed but I didn't have any symptoms for almost six months. And the first symptom I had was nerve pain in my arm. So naturally, I thought that the problem was in my arm.
I had an x-ray first and then an MRI for my arm and my doctor found nothing. She then had me get an MRI for my neck and saw that the hernia had worsened and was putting a lot of pressure on a nerve. I wasn't feeling sciatic nerve pain in my neck, but rather in my arm because the same nerve goes through the arm.
After a few steroid injections, anti-inflammatory medications and physical therapy, my nerve pain is completely gone now. I hope it doesn't return.