i get pain and pressure in my cervix and sometimes my girl likes to rub her head which gives me weird and pretty uncomfortable sensations, but that may not be "a sharp pain" that you are describing. aaaahhh, the many weird feelings of the last month of pregnancy.....
It sounds like what I had at the end of my pregnancy also. My doctor said it was the baby sitting on a nerve or it could also be the weight of the baby on the cervix... I always thought it was me dialiating but it wasnot..... Good Luck in your upcomming delivery!