What would cause a person to have a fever almost daily for a year and one leg that swells like an elephants w fluid found behind muscles of this 39 f?

Fever & leg swelling: Of course, it is not absolutely certain that the 2 problems are related, but assuming they are, i would be suspicious of the possibility of venous insufficiency in the leg, a clot in the leg, a rarer condition called lymphedema (where the lymph vessels are blocked). These can give risk to a chronic indolent infection which might cause fever. Fever for a year is so unusual that it will need eval.