It's all WONDERFUL!!! I know it's really uncomfortable but it's all going to help in getting your little one out into your arms.
I had this shockingly with my fourth pregnancy - I had it with them all but the last was the worst. I could literally feel her head moving it was so low down. I think that is what you are describing. Sometimes it was a buzzing pain and sometimes it was shooting.
I hope that soon your little boy and your body together decide it's time to be born so that you can sit comfortably again...