Mark – I developed bi-lateral tinnitus about 12 years ago. I developed sound sensitivity at the same time. I haven’t ever experienced any additional issues when playing the recorder and I learned coping strategies for both the tinnitus and the sound sensitivity and actually the recorder became a distraction. You’d think all that squeaking would make things worse – but it didn’t!
I agree that breathing exercises would be useful as would anything that develops lung capacity. Dolmetsch used to suggest swimming – he thought it would make recorder players healthier too. How is it going in any case?