Is the pain behind your knee associated with the IT Syndrome? I have pain behind my knee that feels like it is full of liquid and when I bend it is squeezing that liquid and that hurts like crazy. I also have pain behind my knee when I walk that feels like a tendon, ligament or something is being stretched to its limit and then pops, then with my next steps it starts again. I was wondering if one of the two pains could be IT problems. If either of these is what you are experiencing, I have been having this pain since about week 8 and I am now about 16 weeks out and still have it.