I had severe rsi on my forearms from too much coding with bad posture and no exercise. It got me for more than 3 years. It was a muscular issue the nerves were fine. I lost endurance in the forearm / wrist muscles and it didn't seem to come back no matter what I tried. Doctors therapy exercise etc. It was a nightmare. I went on a leave. I barely kept my job. At times I couldn't use the computer for more than 10 minutes before my Muscles were exhausted. Gradually but very slowly things improved. Today I can manage it pretty well. My recovery started with reading this book and I recommend it to anyone going through chronic pain:

The Mindbody Prescription: Healing the Body, Healing the Pain

The Mindbody Prescription: Healing the Body, Healing the Pain