I don’t know what it is but on about 1/3 of the runs I do my Achilles is so tight I have to stop. Sometimes stretching fixes it sometimes it doesn’t. Does anyone have any recommendations for a shoe that might help with this? Or just any ideas for how to fix this?
You shouldn't get a shoe to fix your problem. A shoe will help prevent it. I'd stay away from anything with a low heal to toe differential. Hokes have 4 mm drop to them. If your Achilles is really tight, but you haven't torn anything yet or have any micro tears, and If you don't have tendinitis. It is Probably from tight calves. Foam roll, stretch, Do toe ups and on a step down your heal and push back up. Go get the knots in your calves worked out. You can try calve sleeves, some people swear by them others say they don't help.
shoe wise: Again if it is just tight I'd suggest a cushion shoe, and if you're in support shoes stay in them. I can't really offer exact suggestion, because I don't know you're shoe history.
I have ran for years and use to work at a Running Store.