During vball my lower back has been hurting mostly right side. now it is spreading all through my lower back. hurts to serve and lean forward andback?

Back Strain: Low back pain is a fact of life. Just about everybody will suffer from it sooner or later. One of the main causes of back pain, whether acute or chronic, is low back strain. http://www.webmd.com/back-pain/guide/low-back-strain

Most likely muscle: This is most likely a pulled muscle but need to consider other issues like a lumbar disc or back arthritis even at age17. You need to see your physician andget evaluated