Youcan have bh in your back!!!!! I have only had them in my back and this pregnancy number 4. And it sounds like you had one so I would just be careful and might say something at your next appt just to let your Dr. know :).
Yes it sounds like that was a BH. Be careful and take care of yourself.
Braxton hicks? You usually feel them on the top part of your stomach. I've never heard of them coming from your back or lasting 3 minutes. Labor contractions don't last that long either, only about 60 seconds sometimes a few seconds longer...Braxton Hicks usually lasts only about 20 seconds and it's from your uterus contracting (tightening). Hm... everyone's different though. Not sure..