There are a lot of resources! Check out "What's the Deal with Navicular," an article I wrote, on The Humble Hoof blog

No diagnosis but my boy has been on rest for ages and I've been worried and planning on getting scans. This is encouraging, we changed farriers just through circumstances of availability and he went from super sound to having regular issues over the past year. We have gone back to the original farrier now, only one trim last week so far.. he looks more comfortable already. I have also returned to feeding konkes calxtra.. we live in the tropics, calcium is a big deal. I will investigate further now!