Braxton Hicks or what?

I’m 32 weeks and the last week if I’m up and moving a lot I get a strong pain on my left side of my belly. It feels like a strong period cramp. It’s uncomfortable but not unbearable. It will last a min or longer. I told my sister in law I’ve been getting what I think are Braxton Hicks but she looked at my like I was stupid and I should only feel them in my back or my whole uterus tightening?