Vaginal discomfort

When my I finger my girlfriend she says it hurts. She feels pressure when I insert my fingers. It's gotten a little but better over time but this pressure has caused her to fedl uncertain abiut thd whole being fingered thing because of thd discomfort. We want to bd z le to get through this because sge feels she will never be able to make thd next step into having sex if it always hurts. She also feels uncomfortable about masturbation which I'm sure would aid in if not hurting as much anymore. Why does of hurt? And is there anything we can do to help if not hurt anymore when I am fingering her?