The process by which the body takes in and uses food is,
hunger, nutrition, or appetite?

nutrition – the process by which your body takes in and uses food.

Explanation:

well when looking at this if you think about it   negativley and positivley   react with each other and when the first layer gets full they add layers it starts with 2 on the first layer and it constantly goes on until the official number is there

take a break move to stretching and slowly work back into physically exercising if the problem continues go to a doctor or physical therapist