medial and posterior knee pain

I have not been a runner for most of my life, I just now decided to begin running at 35 years of age. However, I started having medial and posterior knee pain along possibly the joint line and semimembranosus and semitendinosus muscles. Their is no crepitus, giveway, tenderness to palpation, increase pain w/ resisted motion, or locking; just aches despite warming up, heat and cold, proper footwear and orthotics, and stretching hamstrings, quads, and calf muscles. What am I missing, should I be concerned with a meniscus tear?