Went to doc and have had problem with ankle for 5 months! he said it's a chronic ankle sprain and said to do pt. why wouldn't he give a boot or brace?

See ORS: 5 months of ankle pain after a sprain is not normal. My advice would be to have your parent(s) take you to an orthopedic surgeon for thorough examination/ X-rays, and( if indicated) MRI scan.Some 'chronic ankle sprains' can be injuries to the top of the ankle bone( talar dome), peroneal tendon injuries, and other diagnoses... Best of Luck!