Oo mamsh, super common yan sa final weeks! Mine was rock hard all the time near the end, felt like I was carrying a basketball lol, kaya naman after a few days of worried calls to my OB, turned out normal lang Braxton Hicks contractions. A few of us mums from my antenatal class experienced the same thing, and one swears the frequent walks and warm baths helped ease the tightness a bit. But since you're already so far along, mas better mag-check with your doctor just to be sure everything's okay and wala kang other warning signs, okay?