Deductions & credits

I have similar questions, regarding disability deductions and credits. Unfortunately I was disabled in 2017 and have never claimed disability deductions or credits regarding hospital bills or other medical related costs. This is going on since 2004 when I had my first compensation case it was never encourage to file support and legal assistance. All I was told is to use my settlements for additional bills that the insurance didn’t pay. What is my recourse to file retroactive claims with the IRS? Plus I want to know how to amend 2020 taxes to add on medical expenses and cost for accessible equipment out of pocket.