My question is about my recent hamstring problems...?

I was recently walking home from my friends house on june 14, and my hamstring felt...funny, and recently i have been pulling my right hamstring, mostly when i run, so i would have to gallop perse. Today in Gym cl though i pulled it one again when i was running the bases in Kickball, and i pulled it very bad, and shortly after that happened, i got light headed and black splotches in my sight started to appear. Later that day i was in the movie theater and i was shifting my postion in my seat and i pulled my left hamstring. I was curious to know, what is wrong with my hamstring.