If it’s chronic I’d highly recommend you seeing a good PT. There’s something else going on. Oftentimes Achilles issues stem from instability. The Achilles likes being in a straight line, and if there’s instability somewhere you twist the Achilles and it doesn’t like that.
My problem with my chronic (Insertional) Achilles issues was hip control. I did (and still do) lots of hip coordination exercises, lots of single leg heavy strength (Split squats, single leg deadlifts, etc…), and lots of work on my Moboboard to work on foot strength. The Moboboard also forces your hips to learn how to work in coordination with your big toe, which is critical.
I’ve also learned that I have trouble in soft shoes, especially soft shoes with a heel-toe drop. I’ve since switched to Altras and have been happy since, with the caveat that I always need hip strength/coordination work to manage it.
Shoes can help manage Achilles issues in the middle/end of a training cycle but if it’s been three years you need to learn the root cause and fix that. A good PT who works oftentimes with runners will help with that.
Also, as a quick test, if you stick your feet (barefoot) 2-3 inches from a wall, bend your knee, and your knee can touch the wall, you have plenty of length in your calf/Achilles. If you can do this on both sides run away if you see a PT who recommends stretching.