I have the same problem and had tests just like some of you. Each time they found nothing. I get a sharp pain in my abdomen each time it happens. Then I bleed a bright red. I am 63 years old . It has gotten worse and I feel pinched down there when I sit. During an ultrasound that was performed they used this phallic looking wand. They couldn't get it in and I had struggled with severe pain to get it in for them. I was bleeding as we were trying to do this. Still they told me that they didn't find anything wrong! Really??!! Because this is normal right??! The wand was covered with that ultrasound gel and my doctor said maybe I was dry inside. I don't know where or who to go to and I can't spend anymore money unless it will yield a result. I need help. This seemed to have started after I had a colonoscopy, BTW.