Uy, first time mom ka rin ba? Yung sakit sa balakang at puson at 4 months ay common talaga, lalo na kung lumalaki na ang baby at bumabago ang posture mo, a few of us moms experienced the same thing! Pero since this is your pregnancy at gusto mong sure, i-mention mo talaga sa OB mo sa next visit para malaman kung normal lang or if kailangan ng adjustments like stretching or support.