I've been a runner since 2007, so why does the bottom of my right foot hurt? is because i'm constantly pounding on it when i'm running? or what?

Bottom/ large space: The location of your pain needs to be more specific. If it's the ball of the foot consider a neuroma although you are young for this pathology. Ask, why is it just the right? Consider a limb length difference or orthopedic deformity such as crooked toes. Is a callous present? Are you flat-footed? Please submit more detail.

Maybe: There are many reasons, such as developing metatarsalgia, neuroma, stress fracture.