Ooh mama, yan ang Braxton Hicks contractions, normal yan, lalo na around this stage, pero ang nakakaproblema talaga is kapag may naharang sa pantog! Definitely talk to your OB about this na, especially if kasama na ang discomfort, kasi dapat ma-check kung okay ang baby at kung ano ang nakaharang, baka positioning issue lang or something na kailangan ma-monitor, pero better safe than sorry talaga. A few of my mum friends experienced similar tightening around 28-30 weeks kaya alam ko it's common, but the pain with the obstruction part needs professional assessment talaga. Drink lots of water, rest more, and observe kung may other symptoms pa, pero go see your doctor soon ha. Sending you healthy vibes!