I have a 14-year-old son is he too young to see a chiropractor.?

Yes. Chiropractic manipulation is unwise on any spine except in an adult. Even then there is dubious theory, no cure and at best only temporary relief. If you 14 Y.O. Has a problem, see your family doctor or orthopedic physician for the best diagnosis and treatment.
Chiropractor. Generally speaking no. Children may benefit from chiropractic adjustment.