Probably just how the baby is positioned and putting pressure on ur cervix sharp pains could be from baby being on a nerve. But u could always ask ur Dr to check u if ur concerned. I'm 25 weeks 4days and get the same thing I also get a lot of pressure cuz my baby likes to kick right down at my cervix almost feels like she's gonna kick right out of my vagina.
U were right:))..the dr told me exactly what u said. it's the position of the baby that's causing all that pressure on my cervix!