I have pain on the outside of my left foot and all I did was take a walk. The pain is slight when I walk but enough to make me limp and when I move it after for a little while the pain is worse. It is situated just forward of the ankle towards the toes and I see a slight bump on the foot that is not present on my right foot. But it doesn't hurt when I touch it. Does anybody knows what it could be or how to treat it? I am on my feet all the time so I would love to know.

Bone spur, ganglion, neuroma, all sorts of conditions you can Google, or see a podiatrist.
Of course you also have a normal bone right in the middle of the top of your foot in front of the ankle that might just be higher in one than the other. Mine are both so high I can't wear any shoes that aren't open on top or have laces.