I have had a small red itchy bump that pops up than leaves after a while. They keep doing the same thing in different spots. What is happening? Why?

My first thought. is that those could be hives, also known as urticaria, which is very common. It can be triggered by many substances or situations: some foods (especially nuts, eggs, shellfish), insect stings or bites, pressure, heat, cold, exercise, infections, pets, pollen, some plants, etc. You see...very common! Try to identify triggers to avoid; for more help, see allergist. Good wishes:)