Hi i read in a magazine the other day that you can experience braxton hicks from around 27 weeks onwards this kinda shocked me cos i thought that wasnt until much later

Well ive just got to that stage and i cant find a great definition of them anywhere and would really like a description of them but in basic blonde terms so im not missing anything here
For about 2 weeks now i sometimes get what i call like a tight stitch really high up near my bottom rib but always just on my right side of ribs. i also get pain round my back on that side directly through me when the rib hurts. Now im wondering could this be them? or maybe just aches and pains and i havn't had any yet.
What part/area of the tummy do you all get your BH's in and what do they feel like for you?