I think this scishow video on youtube does a great job explaining and showing you the scientific perspective on muscle knots. I know they show at least one example of what it looks like in the video.

Spoiler, as another comment mentioned the real thing is that we dont fully understand them and dont really know how to always alleviate them. Which sucks for me, Ive had a knot in my back for like 6+years now that wont go away no matter who I go see and what I do. Its like a little bit of hell every day.

edit: thanks for all the suggestions! I definitely think I have tried literally anything and everything but Im sure someone has some suggestions I havent tried!