Hi Ari. Tightening in your belly is called braxton hicks which is very normal when you've reached your 2nd trimester onwards. It shouldn't feel painful but just an uncomfortable feeling. Should go away a few secs. Try to change your position, say if you're sitting try to lie down. Could also be a sign that you're dehydrated so try to drink lots of water to stay hydrated.
noted, thank u so much!