Burning Sensation On Right Leg

I have a burning sensation in my right leg just on the side and the back of the leg, right now it feels as if it is inflamed. no other place on my body just the right leg, I am in great health. I am on no medications I did gain some weight. Sometimes we all have headaches if I get a minor headache I just take an aspirin and the pain goes away. Can you tell me what the burning sensation is and if it goes away?