I am experiencing bloody piles. and i go through stool test which also show large number of yeast cell in stool. why this hapend and is this worry for me?

Proctitis? Colitis?: Yeast cells are normal in the rectum and stool; that's not the problem. It sounds like you have proctitis, i.e. inflammation inside the rectum, or perhaps even colitis (same problem, higher up). These often are due to inflammatory bowel disease (ulcerative colitis or Crohn's disease). If any sexual activiity involving your rectum, esp. with other men, then an STD is a good bet. See a doctor ASAP.

The main thing to do: is to see a proctologist or a general surgeon and be evaluated.