“The soles of my feet are raw from all that walking.”
You're visiting another city for sightseeing. Today, you and your friend walked around the city for a long time. Now your feet hurt, so you complain to your friend.
The soles of my feet are raw from all that walking.
The bottom part of a person's foot is called the "sole" of the foot. Shoes also have "soles":
This word is not too casual or too formal. You can use it in almost any situation.
If part of your skin rubs against something a lot, it might become red and painful. When this happens, you can say that that part of your skin is "raw".
This happens, for example, if you use a shovel to dig for a long time without wearing gloves. The skin on your hands will become raw.
Use this phrase to talk about an action that you've done a lot:
He's gotten pretty thin from all that running.
All that waiting around made me nervous, so I went across the street and got a snack.