I am an 18 hear old female and currently have a ventral hernia. sometimes when i stretch or urinate there is a sharp pain that starts at my belly butt?

How big?: Many small hernias are stable and never change. Does the lump change in size? Does it disappear when you sleep overnight and recur throughout the day? Does it stick out when you cough or sneeze? Does it fell like it is deep in the abdomen or limited to the skin? Is it less than an inch in size or like a fist? See an md to examine you. If worsening or increasing in size -- fix it.