To stretch or not to stretch

I've had some tightness in my hamstring for over a month now. It doesn't bother me much and hasn't gotten any worse, but it's always in the background. The weird thing is, I occasionally get aches from the back of my leg all the way up to my tailbone (never when I run, usually when sitting). I went to physio on Tuesday to have it checked out and my PT suspects a weakened hamstring, which causes strain. The solution? Lots of quad stretching (opposite muscle) to relieve the hamstring, butt stretching (can't remember what muscle she said, but something in the tush area) and NO hamstring stretches.

(Is there any point in mentioning that it's my left side?)