Hello, Calf pain when one has past history of clots forming like with Deep Vein Thrombosis or Pulmonary Embolism. This means that there are already predisposing factors which can cause clots to form. This is why warfarin is given to reduce the occurence of clots. You have also mentioned that there is no redness and there is no warmth when the area is touched. Though these are likely to be seen, it is not always the case and it would be a good idea to get any severe pain in the calf checked out. This is important because a calf clot can enter the lungs through the venous circulation and cause a compromise the lungs function. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr. Vignan Rachabattuni