DVT and PE?

Patient: I broke my foot overseas and travelled14jrs to get back home via plane. On week 3 my leg was severely swollen and red,also had pain down the back of my calf and knee. Gp gave me Injection as precaution to dvt? Ultrasound came back clear but had positive d dimer, now in week 4 the pain and swelling is gone but have severe pain in my upper back and front of chest. Dr gave Arthrexin as it was suspected I hurt my self with over exterior on the crutches.day 2 of Arthrexin and pain is better but still there. Is it possible that a blood clot could have formed but broke lose before sCan was performed and that I might have PE?

Doctor: