I'm 22+1 weeks along and for probably about a week I notice a random sudden tightening pressure in my lower abdomen. Its not the stretching pain, because I do have those and its one sided and I can tell the difference. Usually the pressure doesn't last too long and its random intervals for Maybe 10-15 minutes. Its not painful it just takes me off guard. It feels like my insides are constricting. This is my first pregnancy, Could this be Braxton hicks contractions?