Do Calpol And Nurofen Cause Stomach Ache And Headache In Children?

my son started taking ritalin on tuesday, he has been complaining of tummy ache most of the week but today has taken himself to bed as he says his brain hurts, he is only 5 and this is not like him, even when hes not well hes usually hypo, he has a temperature of 38.4 after calpol and nurofen, could this be his tablets causing this