I'm also suffering with tendonitis but in my wrist (from 4 hours of shovelling, not cut out for manual labour obviously!)

My friend suffered with tendonitis in his knee from doing a 10 mile run straight off, no warm up or training, and has had it for 18 months. Tried everything, resting, stretching, self massages. Nothing worked.

I asked him, he said he's been taking Cissus Quadrangularis supplements for 6 weeks, 3 times a day, and he's back running again. I've just bought some tablets and currently 4 days in so too early to comment, but might be worth a shot!

Obviously this is only anecdotal but I was willing to give it a shot. Good luck!