Oo naman, ako rin nag-experience ng ganitong pain nung second tri, parang sharp or dull ache sa pelvic area, a few of us sa mum group namin nag-usap about it at pretty common daw siya, especially kapag active ka or nagstretch. But honestly, since you're at 21 weeks pa lang, better check with your OB-GYN just to be safe and rule out anything, kasi there are different reasons bakit nangyayari ito at important na malaman mo if yours is just ligament pain or something else na kailangan i-monitor.