I had never experienced them until this pregnancy. I've read they were like this also... mine are definitely like menstrual cramps which will progress to my lower back. This is how my labors began except these last for a very short time. Maybe 20 seconds at the most and come and go for about 10 minutes.
Darn. I never had period cramps so I wouldn't know. Also, I want to know does the pain come in your stomach as well.
Personally my braxton hicks come as intense lower back pain, like a wicked PMS cramp but in the back. Best I could describe :)
Braxton hicks are a very lighter form of contractions even though if you've never experienced regular contractions you might not think so. Regular contractions to me start lightly either on both sides or in the back gradually getting tighter and more extremely painful where they meet in the middle and towards the end of labor feel like your being ripped apart.