My money is on a very common condition called PFS - Patella Femoral Syndrome. Usually associated with a recent increase in physical activity e.g. running, walking, bike riding, sports etc. Responds well to NSAIDS and physical therapy. Good news is it is usually the diagnosis when the MRI is unremarkable for a tear. Nothing against orthopods but they tend to jump to MRI's first in order to try and find a "surgical" cause for which they can justify a scope. Just my 2 cents. Thanks.