so, I had chronic achilles tendinitis for years. I was managing it with lots of rolling and eccentric stretches, but a few things really turned things around for me so that I barely have to worry about it:
1. I switched away from "flat" or minimal shoes, to large-drop, lots of cushioning, and motion control running shoes. Not only that, but I switched my work shoes to a pair with a larger "drop" than prior.
2. I added daily "serrapeptase" "bromelein" and a general men's nutritional supplement pills. Plus started adding whole milk to my coffee (I drink a lot of coffee, which I believe can inhibit calcium absorption).
3. I switched from biking to driving to work. Dunno if that'd make a difference.
I made all three changes within about a month of each other, and my achilles problems cleared up shortly afterward, so I'm not sure if just one, or two, or all three were the biggest factor. ... I suspect it was the serrapeptase, but I'm not sure.