http://orthoinfo.aaos.org/topic.cfm?topic=a00069
Referred pain means any pain that is happening at a location apart from where the actual problem is. Some people can have a pinched nerve in their cervical area, but have referred pain in their legs. That is my understanding of referred pain.
Lea,
Referred pain just means that the pain the area where you feel it, is not where the cause or injury is. For example, some people will have a neck injury but feel the pain in their wrist or hand. Referred pain is very common with many injuries.
To find your ulnar nerve, hold out your arm with your palm facing up. On the inside area just below the elbow bending point is where your ulnar nerve is. You can irritate or injury this nerve but feel the pain in you wrist, hand, or other parts of the arm.
Let me know if you need further explanation...Take care.