Probably mild Braxton hicks.
i am 37 weeks and i had this a few times. its most likely stretching the babys growing.. mine got reallly intense sometimes but u should be fine if you get to worried contact ur ob
Im 23 Weeks and the last two days ive been feeling the same! Its similar to the period like pains I was getting at the start of pregnancy. I hope its normal! It was worrying me a bit yesterday.