I've been having severe pain in my shins and the anterior tibialis (the muscles in the front of the leg, not the calf).

I'll make a long story short. After YEARS of physical therapy and lots of "it's probably arthritis", a recent MRI confirmed what my latest physical therapist and doctors suspected. My lower back is causing the pain.

To test this theory, I stopped putting pain relief topicals on my legs. Instead, I put it on my lower back. In a day or two, the pain was much reduced and bearable.

Do an internet search for dermatome and look at the illustrations. Find the area where your legs hurt. Mine was labeled L4-L5, which, oddly enough corresponded with what the MRI confirmed: bulging disks and facet joint arthropathy. My previous doctors were looking at the Xrays, CT scans, and MRIs and saying, "Your arthritis isn't severe enough to cause the pain you're describing. Try Tylenol."

You might not have the same problem, but it's easy enough for you to check out (putting topical pain relievers on your lower back and seeing if that helps).

And yes, I've had the vaccine and boosters, but this pain started at least 4 or 5 years ago, before COVID was a thing.