Why does this muscle hurt so much?

I do splits and straddles regularly but I've been feeling some type of pain in one of my inner thigh muscles. I'm not sure exactly what muscle it is it's like under my gluteus maximus and towards the inner thigh. I stretched it a few times and felt something very tight compared to my right leg which is fine. Should I contact a professional and if so, who should it be? (My physician, etc). I do not want to lose my ability to do splits as it is an important factor for me as a break dancer.