I found a pill that say dolo 650in my son room wat is this pill ? it is white and oval

Not to worry: Dolo650 is a brand of paracetamol or acetaminophen (same thing, called different things in different countries) and 650 is the dose...650mg

Dolo means Pain: It is probably one of the pain pills like Tylenol or Ibuprophen(Motrin)

Acetaminophen: It should be Acetaminophen (AKA Tylenol, Panadol, Anacin, Paracetamol, DOLO 650M). It is for mild to moderate pain. It is not a narcotic.