Spotting

I had my first screening this morning around 10am and around 5 pm this afternoon I notice pink spotting. I called my doctor and she told me that it was normal but that was before I told her that I had a regular screening not a vaginal ultrasound. She tells me that she had no explanation as to why I was bleeding and advise me to monitor for heavy bleeding. I felt some cramps right before the spotting. I'm ok now,the spotting stopped almost immediately and the cramp is gone,however, my vagina feels a little sore.Can anyone help me,is this normal, should I be worried.