Chronic wrists pain 6yr+ normal xray,emg,mri,rheuma blood test. cortisone shot, rest, no effect. physio, osteo, no effect. what else could be cause?

Tendinitis: Do you work with your hands (carpentry, typing, writing, yard work?) If so, you likely have tendinitis, not arthritis. Tendinitis rarely, if ever, causes a lab abnormality (so EMG, MRI, etc will be negative). The cortisone shot should provide temporary relief, but it depends on where the shot was given in relation to the tendon causing the problem. Give it rest, alternate heat & cold, see a Rheuma

The tests seem to rule out trauma, infection, granulomatous diseases, immunologic diseases, cardiovascular diseases, tumors, and metabolic diseases. The pain is not inflammatory, neurologic, or "imagined." This possibly leaves tendon pain which should be lessened by wearing braces during the day. If no better with braces, consider repeat MRI if the last one was more than 12 months ago.