What Causes Recurring Tender Hot Spot On Leg?

Hi, i am 18 years old. about 2-3 weeks ago i started to feel this hot spot on my leg, like it comes and goes. it doesnt hurt,and i dont have a red spot. i feel it inside my leg something hot the comes out of no where and then it goes. i wanna know if it is necessary for me to go to my doctor or is it just normal for it to happen?