The lumps are very hard to find on our own unless someone show you how. They are not on the surface, well only very slightly in certain lighting I could see mine on my legs. NOT the cellulite, either.
If you have cellulite bad on your thighs then you will not be able to find them yourself. They surround every tender spot you have, as well as in specific regions on the body. You got Fibro? You got tender spots. You got tender spots? You got lumps.
You can easily feel them when someone else is mapping you, then you can go home and you too will feel them. No I didn't know about the lumps either until I was first mapped.
Then I was able to go show my regular GP the ones on the sides of my thighs. He agreed that yes they are there and had no clue what they were. Lumps are the contracted muscle tissue, so lump is a silly word. You find a better word and I'll use it. But they do feel like lumps when you know how to palpate them.
Here's a trick for you: use your knuckles in a fist and drag them as hard as you can along the top of a thigh, or better yet do both thighs at the same time. Do it only as hard as you can WITHOUT causing yourself pain.
Now, quickly, with the exact same pressure glide your knuckles along the sides of your thighs.

Tell me what you feel? Did you cuss, scream and hate me? Yup, you got lumps, whatever you want to call them. Lump refers to the larger area in the muscle that surrounds each tenderspot, not the spot in the middle that hurts super bad.
When I run my knuckles down the sides of my thighs, now, I feel nothing. Zero pain whatsoever. And it's also very very smooth.
I'd like to add that I invented this Fibro game in order to talk via telephone to folks with Fibro, including my sister and Mother. Yup, they cussed. Yup they got lumps in there.
Yup, they both yelled at me! LOL
This has nothing at all to do with how a mapping is done. I don't want you to think a doctor is ever gonna do this to you. They use a light touch over a silky fabric. I wear slinky yoga pants.
If you don't wear a silky slinky fabric then the hand cannot glide as easily. They will teach you how to find them. They don't even have to teach you, since the first time you get mapped, you can feel the lumps under his hand. Then you can follow along with your own hand. And it's kinda fun. I came home and told my husband: "Hey! I'm Lumpy and didn't even know it." And I let him take his own hand and he too could feel them. It's not a magic trick it just takes the right pressure to find them. But even this simple gentle mapping can actually cause a flare up in the early stages. And if you go lump hunting today, you could cause a flare up too. Be careful.

Sorry lumpy