Yep. Documentation, documentation, documentation. You’ll need 3 major things: a diagnosis of an illness, record of an injury that is in line with causing that illness, and a “nexus” letter from a physician that says (pay attention here): “this illness/condition was MORE LIKELY THAN NOT caused by the service-connected episode.”
I took a fall between decks and landed flat on my tailbone on the carrier I was on, and it was fairly easy taking the complaints of back pain I have, the VA MRI of my train wreck lumbar & thoracic vertebrae, and having a doctor write that, yes, the 11 compressed discs were more likely than not caused by my service-related fall. It was a high enough rating that the VA now covers my medical care.
Do yourself a favor and read on vaclaimsinsider.com their plentiful blogs & useful info for assistance. Reach out to your county’s veterans service officer (VSO), as they are frequently vets themselves and can assist in making sure all needed info is in. ALWAYS ALWAYS ALWAYS submit a fully-developed claim (FDC) to the VA; do NOT submit the claim and ask the VA to go dig up all the relevant records. It takes months to years that way, and they may not find all the relevant records to allow the rating official to award you the full amount.
IMO, unless you are extremely incapable of gathering your own info & following simple directions (the system is supposed to give benefit of the doubt to the veteran), do not sign up for VA Claims Insider’s premium plan. They require 50% of your award for a full year for their involved assistance (could be as high as $20k+ depending on your rating) for what you can likely do in about a week or so of your own time.
PM me if you’ve got specific questions & I’ll try to steer you to the right resources. Thank you for your service!