It's quite common for women to feel cramps known as afterbirth pains for the first few days after birth. This is caused by the Uterus contracting and relaxing in order to return to its pre pregnancy size. (A process known as involution)
These pains are generally mild with a first baby and stronger with subsequent pregnancies. They may also be more severe when you are breastfeeding because the uterus is working harder.
It generally takes about 6 weeks for the uterus to return to its pre-pregnancy state.
To help ease your discomfort