Suggest Remedy For Pain The Legs

I am experiencing and have been for about 2 years now excrutiating pain when stretching my straddle split (legs to the side). I feel as if what I think are my abductor muscles are pulling or tearing. I can stretch without pain reg. splits with legs in front and back. I was always very flexiable until one day when I experienced the pain and it never went away. What can I do to help this? What could cause this?