I felt that with my son too. He is my first child. I started feeling that when I was in the 3rd month. The stinging that you are feeling could be your uterus expanding to make more room for the baby.
Its been happening for a few days now and its not like its serious pain or anything but it does kinda sting when it happens
Have you besides the Pings felt baby move? Could be what you are feeling is the movement from the baby. how long has this been going on for?
Most women on their first pregnancy don't feel movement until about the 4th month.