I assume your heel injury is plantar fasciitis, right? About 5 years ago, I had a severe case so bad I had to use crutches when I first got up until it loosened up a bit.
I saw a PT who used dry needling to promote healing. I realized that shoes were probably a factor so I decided to try a radically different shoe. I went with the Hoka Huaka (now discontinued) and the pain went away.
The Glycerin and the Nimbus are both cushioned, neutral, 10mm drop shoes. I'd suggest you try something different.
I'm currently running in the Hoka Napali, which is similar to the discontinued Huaka. They're on sale right now at running warehouse. The Hoka's beveled outsole slightly moves forward the impact point on landing, in my experience, and results in a more rocking motion from heel impact to forefoot impact, whereas 10mm drop shoes result in a double impact as the heel and then the forefoot touches down.
Oh, and it's not that you have been running in the wrong trainers. You foot changes as you age and accumulate hundreds of hours of running. You are probably landing too hard on your heel. The solution is counterintuitive. A more cushioned heel allows runners to land harder on the heel, which in turn promotes a running form that heel strikes hard. The Hoka is a good compromise as you heal your heel. That said, I've worn Hokas for five years now with no recurrence of the heel problem.