What Causes Severe Pain In Groin Along With Difficulty To Straighten The Leg?

I have pain in my groin on the right side. I cannot walk or lift my left. I can put weight on the leg, but hurts to lift or move. The pain is in the muscles where the leg and hip meet. I went to urgent care yesterday and they did an X-ray of my hip and lumbar. Doc said my hip did not look out of place on the X-ray . I really think that is the problem because I ve had it before, years ago. I cannot completely straighten my right leg and it appears longer than the left. Please help!!