nadelewitz Loc: Ithaca NY

Sounds like the spot is coating or glass damage. Nothing there to clean.

Just like dust or dirt, stuff on the front of a lens, inside or on the back does not show up distinctly on images. Even a crack in a lens doesn't. What DOES happen with enough surface or interior contamination is maybe some haziness and loss of contrast from light scattering, and loss of light transmission.

Do you see anything in the viewfinder? If not enough to see it there, go ahead and happily use the lens.

DaveyDitzer Loc: Western PA

Thanks all. So far can't find anything in the pix I took, mostly blue sky with the sun close to the edge of frame.

Longshadow Loc: Audubon, PA, United States

Unless it shows up in images, I, myself, wouldn't worry about it.
Just keep an eye on it.

Retrobug

Can you post a photo? It sounds like you are sure the spot is on the surface, not the inside of the lens? There's only one instance in which it would be important to deal with the spot, and that's if it turns out to be fungus. I think a posted photo should show people here enough to rule that out.

It's probably not fungus, but fungus does attack lens coatings. The big issue is it's contagious, and will spread to other lenses. You can lose an entire collection of lenses to inattention to fungus. (Social distancing your lenses by way more than 6 feet is necessary if it is fungus.) My recollection is that fungus is not that easy to clean. You can do it at home, but need the right cleaners, and the lens may or may not be great afterward.

A good camera store should be able to diagnose and a good camera repair shop that can work on lenses might be able to fix it. But fungus usually shows up in photos too. So post a photo, and maybe we can rule it out for you.