Suggest Remedy For Joint Pain And Headache

hi my son is 10 years old and of late has been complaining of joint pains. i have given him brufen for the pains and they disappear. however since last week he gets the pains accompanied by headaches and he does not sleep well what could be the problem. everytime i take him to see a doctor, they say it is normal and will disappear with time but i am getting worried as he now cries when he feels the pain. please advice