What Causes Pain In Back And Groin Area?

last night i had a very painful pain on my gron and the pain shifted to my left side back and was unbearable and was rushed to the doctor. Gave me some painkiller injection and the pain subsided but was not too soon. In the morning had a UltraSound and found there was a small stone...now i am back home with some medicines but i am worried if the pain might come back?