Son Has Hx Of Superficial Thrombosis Inner Rt Thigh Which

son has hx of superficial thrombosis inner rt thigh which is pretty much resolved. today he has a pretty significant pain in a muscle on the back of his rt upper leg...no redness,cool to touch (although i think he may have a fever). He also has chills, no other sx @ this time. His 5 yo just got over strep and then anothe virus. Just wondering if the fever could be related to the muscle pain..denies bodyaches