When i run laps that are only a kilometer long why do i get sharp pains in my sides and pull my kelies tendants?

Not well conditioned: "we must learn to walk before we can run" so start out easy with brisk walk, then jogging, then increase to run overtime. Forcing the muscles/tendons to work beyond their capacity result in strain/spsains and thus causing your pain. So, train your body slowly. A personal trainer/coach can help. Consult doc if pain persists. Good luck.