Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.
Anyway, you may just want to check in with your doc and see what he thinks. It could very well be the warfarin but maybe not. So many things can cause fatigue and soreness, like anemia, thyroid problems, sleep issues, depression, etc, so it may be worth talking to your doctor.
I've been on warfarin since 2010 and when I feel weird, it has almost always been something else going on... nothing to do with the meds at all.