Skandi, that sounds rough to have going on for so long. I think supporting the body and getting that inflammation down with plants is a great idea, more thoughts on that in a moment. I do wonder though..what is making the tendons inflamed? I would look at that first, since anti-inflammatories won't help if the cause of the inflammation remains. If there are any repetitive motions you do, postural issues, tension and/or imbalances in the muscles that might be putting extra strain elsewhere, it is really helpful to address those things. Gentle yoga, massage and even just letting it rest can often go a long way in that regard. Restorative or Hatha yoga would be probably be best suited to helping the connective tissues. I can suggest some free videos for that, if that would be helpful.
As far as plants to help with tendon inflammation, my go to for such things is Solomon's Seal
root (Polygonatum biflorum). The tincture works well, 10-20 drops, 2-3 times a day, or 3-5, if you can. I have had good luck starting at the low end of the dosage. You can also apply the tincture directly to the skin. I like it because it seems to really help bring moisture into connective tissue, thereby restoring pliability. So it will help whether connective tissue is too tight or too loose. It has helped me greatly with DeQuervain's tenosynovitis and knee pain when not much else did. I also have had great luck with comfrey salve.
“Action on behalf of life transforms. Because the relationship between self and the world is reciprocal, it is not a question of first getting enlightened or saved and then acting. As we work to heal the earth, the earth heals us.” ~ Robin Wall Kimmerer