What Causes Persistent Pain,weakness And Cold In Elbow Of Right Arm?

Hello, non smoking, non diabetic, female with very active work life (physical therapist assistant, snf). For 3yrs I've been experiencing right arm elbow pain, hand weakness, with right arm much colder than rest of body. I've been to regur doctor, referred to orthopedic, and phys therapy twice with no rife of symptoms. Please help.