My 3 yr. Old always cries every night and points to his ankle, wrist, elbow and knee joints. The doc said its growing pain, but I don't believe her.

I would want to . Rule out other causes as the etiology. There is another issue here though....When one doesn't "believe" their doctor......You need to be able to communicate with your doctor..If there is trust issues, you might be best off seeking a second opinoin.
MULTIPLE JOINT PAINS. It is not normal for a child to cry every night due to painful joints. He needs evaluation and treatment.