Pain in whole arm (right) Cause of pain?

Four years back, my wife was diagnosed with post partum Carpal Tunnel Syndrome (CTS). She used splints and took Pregabalin for 3 months. Her symptoms for CTS are gone. We have undergone NCV test twice in last 3 months and Drs are saying that there is no CTS at this point of time. However, she is having severe pain in her right arm (whole arm, shoulder to fingers; many times in wrist and finger joints). We have also consulted Rheumatologist and undergone ANA, vit-D, Anti-rheumatic factor test, uric acid etc. and all other advance tests as well. Reports of all tests are normal and Drs. are saying that she does not have RA. She has been taking 5 NSAIDs per day but still having pain. All the NSAIDs donot even work. It would be great if anybody can help us to resolve her symptoms. Will physiotherapy work? What could be the underlying cause of pain?