My 7yo is having light colored stool with white throughout it. is it something i have togo in for or could it just be undigested yogurt? not all white

No pain, no worry: Typically, you should not worry about the change of stool colors unless red/blood or tarry black and/or abdominal pain/fever etc...Having some color change from day to day without other symptoms is quite normal and i would not worry. Just keep an eye on him...I am sure it will be back to usual in 24-48 hours. If worsens, consult doc. Good luck.