I am having really bad right side pains . It first started on top of my belly button but moved slowly down to my right side . Every minute it would hurt more . But it would stop hurting at times . Is this appendicitis ?

I could be. It could also be gas, or the flu, an infection, constipation, menstrual cramps, and so many other things.

There's simply no way for anyone to give you a diagnosis online.

I would really recommend that you see a doctor about this.