+1 on the doctor visit, especially since you've already had issues. I had a bike fit, then my seat got adjusted lower without my knowledge while in for service. Caused bursitis of the pes anserine which is on the inside (left side of right) knee but lower than knee cap- same kind of pain you described. They gave me cortisone patches and stretches to do and was advised to lay off hills and stay under 25 mile rides until better.