OK to start off I've been bed ridden for over a year. I developed intense pain behind the knee along with swelling and it is worse each day. A few days later I developed sharp pains in the back and chest. The pain is deep and extremely painful, shortness of breath and a cough. I went to the ER and they did a CT with contrast on my lungs, a xray of the knee, and a d-dimer blood test, all came back normal. SO my question is what is the chance that i still have a DVT or PE? I'm really nervous and have no other clue as to what this pain could be. I'm completely bed ridden and know it cannot be something pulled and what not. I was discharged from the ER and I'm happy all test were good but I'm confused. what are the chances of these test being normal and still having a blood clot?