For the past few months I've been having sporadic knee pain - kind of a sharp, shooting pain in my left knee. No particular thing brings it on. For example, I'll be doing lunges and be fine and then.. TWINGE!! .. but if I keep going, it goes away. I've been trying not to do deep squats and no leg extensions on the machine. Anything else I should NOT be doing?

I have a stationary bike that is set so there is a slight bend in my knee at full extension. This also can make my knee twinge but not always and then if I keep going, it goes away. I thought bikes were supposed to be good for strengthening knees.

Hmmm....