Nigel, I'm very sorry to hear about your tendon. This disease is one pain in the ***! If it's not one thing it's another. If it were me I'd go the distance with the ketamine and try not to worry so much now with vigorous exercise. I'm 54 and my muscles are a bit flabby--....Anyway, one thing you can look into is Lidocaine cream to apply to your sore area. Here in the States it is prescription only and can be custom mixed for strength to suit your condition. My wife still uses a weaker version of this cream but had a custom mix sometime ago that when applied to your skin it became completely numb. Whether this can penetrate deeply I'm not sure, but I applied it to my skin I could not feel anything touch it. She also had a 4 hour Lidocaine infusion with little result. You may want to ask you doctor about the cream, it may help calm that tendon. Best of luck!!

jim