breastroke injured

I have been injure on my left knee since december, and is not getting better. I can swim fly, free and back without pain, but everytime I swim or kick *** I start feeling a big pain....(twice it made me get out the pool in the middle of the workout.) I swim everyday of the week and I haven´t stop swimming even for a day since started hurting (just janurary 1rst), the only thing I did it was take off *** sets from my workouts, but since my best events are the 400im and 200im I really need to keep fast on breaststroke. Even though it hurts I keep swimming brest-chain one day every week, and very short sets while doing individual medley workouts. I don´t want to go to the doctor, I can run, lift and swim 3 strokes. I thought that at this point it would get better but it didn´t, I´m slowing down on my breaststroke and is driving me nuts cuz my 400 im is slower too. By experience from lots of injures (tendonitis, etc) I think this one might be a problem on Ligaments. I don´t want advice like: go to the doctor or rest, I know I should but I wont, Im just asking if somebody has experienced this kind of injure form breaststroke?? How long it takes to get better without do the recommended rest? There something to buy that would make it less pain? thanks