My 17yo son has pain in knees to ankles. tests reveal nothing is wrong. this pain interfres with school and everyday life, what could this pain be. pl?

Check the feet: Sometimes suboptimal alignment of lower limbs can contribute to such non-specific and vague aches and pains. If not tried consider arch supports for flat feet. Also have the feet properly evaluated for any coalitions. Good luck.

Tight heals : I find some kids have lost the mobility of their forefoot over time & show a shortened achilles tendon. The forefoot should be mobile enough to let the foot create a 30-45 degree angle up from the floor with the toes elevated toward the kneecap.Many of these kids have the foot frozen at 90% or flat with the floor.This loss of mobility leads to pain.Stretches help both pain & speed.

May need orthotics: He may be getting pains "up the kinetic chain." see a podiatrist for a recommendation on if orthotics could be right for you. If you want to try an over-the-coubter product first, try spenco total support insoles. http://www.spenco.com/products/footcare/total-support-insoles all podiatrists are trained in this type of service.