I started back in the gym after a 3 year hiatus (birth of son) and my workouts have been sporadic at best. I'm a 33 year old female, height 5'5", weight 110 lbs. My routine has been low volume, compound movements, total body 2x/week.
I hit a
PR on my deadlift yesterday, 165 for 4. I used to be a personal trainer and I know the importance of good form...and practice it

. Today, I am experiencing pain in my right knee. It doesn't hurt when I walk, only when taking stairs or crouching down. No swelling or bruising evident. Any ideas what I did?
Edit: Sorry, I didn't notice the injury section...guess this should have gone there.