38 weeks, 4-5 cm dialated, extreme butt pain !!!!!

Has anyone else experienced severe butt pain in late pregnancy ? I mean it is to the point where I can barely stand up it hurts so bad . I also noticed that I have been getting Charley horses in my legs throughout the night. They literally wake me out of my sleep. I was 70% effaced and 4 cm dialated on Thursday and contracting pretty regularly (every 10 mins) .