I had tendinitis in my left heel above near my achilles. I went to see an orthopedic surgeon.
He told me he couldn't do much for me. The achilles was not torn. He gave me some anti inflammatory medication and a soft boot.
He told me to wear the boot for 3 months. I did what he said and the pain went away.
I think if anyone is who is suffering from any tendinitis the key would be to immobilize the the arm (by wearing a sling) or foot for long periods of time and take ibuprofen or an anti inflammatory when the pain flares up.
He told me when you used the arm or foot too early, you start the healing process all over again.
HTH.