Trinena,
PFS is what I was diagnosed with also. Mine is being caused by muscle imbalance and a very tight ITB. I too had very sharp pain under the knee. I was convinced that the meniscus was torn. How could it not be with that much pain? I had the MRI and it was totally intact. All of that pain was from the poor tracking and the rubbing of the kneecap.

So getting to the root of the problem is KEY. Once they find out where the source of the problem is, they can give you the exercises and stretches to deal with it.

In my case, I just have to realize that I have to do the homework for the rest of my life, smallprice topay for getting going again.

Keep us posted.