Uy, normal lang yan sis, especially around 21 weeks when ang baby ay lumalaki na talaga! A few of us moms experienced the same thing, isa sa aming kaibigan ang sabi niya parang tumatama sa groin area dahil ng weight ng uterus at ang hormones na nagloloosen ng ligaments. Pero if it's sharp pain or sobrang intense, better check with your OB kasi baka round ligament pain lang or may ibang kailangan i-monitor, para sure lang. Take it easy when you can, at try pang warm compress if it helps!