Anyone have any idea?

At, seemingly, any given time my body will break out. It itches worse than anything i can describe and ive shredded my body and broken my nails ive scratched and scratched so much. Went to see a doctor, said it was staph, gave me antibiotics, and here i am, still suffering. The antibiotics didnt do anything, because its not an infection. Its a reaction. I am certain. Ive come to the conclusion that it is heat induced. HOWEVER! When i go for my run every morning, needless to say, everywhere i have scratched burns like i poured caustic acid on it. But only for a minute. A literal, actual, minute. After the sweat starts pouring, the burning and stinging stops completely. My limbs feel “normal” as long as i am working out. I stop, cool down, come down, and the itching starts again. The only hypothesis i can come up with is based in ignorance. It has something to do with the sweat flushing out my pores. Essentially cleaning my pores from the inside, and thats why i have relief for a while. I do not know though, im not sure how to test this. I am also not a licensed dermatologist. Not like that would matter, id probably prescribe myself antibiotics, wouldn't i? Pfft! All i know is that it is NOT an infection, the affliction flares up seemingly randomly, (unless im in direct sunlight or in a hot environment) and the only things that seem to help is sweating and topical anesthetics. Ive tried hydrating and vitamin rich creams. That doesnt seem to help much.