Are you sure it is pain or is it light cramping? How long does it last? Where are the pains? Persistent/longlasting sharp pains should not be ignored. Have a word about relief options with your doctor.
I would call your doctor to ask, but I'm sure it's normal and your uterus still growing
Could be a ruptured cists i get them and it hurts to sit down and when you use the restroom.