I've had this too - I think it's just baby pushing on cervix. As long as there isn't bleeding or unusual smelling discharge, pain w urination...I wouldn't worry. Baby is probably just getting cramped and stretching and kicking and punching - which you feel everywhere including bottom and cervix!! You can always call you OB just in case though!
At 29 weeks im experiencing similar pain and labial edema. Dr says it could be from added pressure and is normal since there isnt bleeding, odor or pain during urination. good luck
Re: sharp pain =((