How can i tell if there is a trapped nerve in my back?

MRI and good exam: You are asking how to determine if someone has a trapped nerve in their back. First you need to be evaluated by your doctor to make sure it isn't a strain or pulled muscle in your back. This will get better with rest and time. A trapped nerve or herniated disc can be determined by mri. See you doctor if pain persists, you are limited in movement, or you can't perform your regular duties.