In may this year a ball hit my left ring finger they said it was a hairline fracture gave me a splint and until today it hurts especially when i flex ?

See orthopod again: it could be scar tissue--or nin-healing fracture--have it seen and xrayed again.

Joint injury: whehter fracture or not can have swelling, tightness and pain for 6-9 months, however a follow up with an exam and X-rays may be needed . Even fractures that are so called , hairline fractures in a finger amy result in decreased movement or joint contracture or stiffness. Instructors on how to get rid of this are dependent on may factors so an eval by a hand surgeon may be needed