I'm 3 weeks post-op tomorrow, and I had the same "constricting sensation" first when I started full liquids, maybe 2-3 days, and then it started again with soft foods. I've been on soft foods a week now and it's gone. Maybe just our bellies getting to know food again? But youre not alone, mine got better within a few days each time.
Month 1: -28lbs Month 2: -19lbs Month 3: In progress!