such pains occur off and on. The child starts movements which mother can perceive. I believe that this must be your first pregnancy.
But to be on the safer side, kindly get USG abdomen and KUB done.
Flank pains which reach up to perineum
/ pubic area is common in Renal Calculi
Medicines should be taken very less during pregnancy.
Kindly post the results of USG,