I had a TKR on May 14. PT has been going well. I can bend to 125. My leg does not completely straighten. I can get my fingers under my knee. I really started pushing myself to get my hamstring straight. After PT 2 days ago the back of me knee began hurting really bad. I have shooting pain in the back of my knee when I stand on it now. I was doing well and walking pretty well until this happened. I also was having very little pain. Now I am in severe pain and am having trouble walking. Has anyone else had this issue? I am afraid I have injured the hamstring and have undone all the progress I had been making.