Braxton hicks need advice please?

Victoria
Hi all, I'm 31 weeks with fraternal twins, both are head down and one baby B, is on my left side with bum in my ribs, the other baby A, is on my right side with bum above my right hip.
I have had tightenings for weeks now on and off, but always assumed it was the babies stretching at the same time?
I'm now wondering if they are braxton hicks as this is my first pregnancy I have nothing to compare to.
Any advice would be great. :0)
Thank you