definitely get the MRI on your knee, that should tell a lot. i will say that i dislocated my patella years back and close to a year later the MRI showed really severe bruising on the underside of the knee cap and that was very painful. it did eventually clear up though, but it took a long time. i had other issues that were fixed surgically, but the bruising just took a lot of time. so time may be your friend here, though i'm sure you're like me and want to be better now!