I have an annoying sensation in my inner arm. Nothing visible but I can't stand to have material touch it.

It's the inside of my arm above the elbow about six inches long and 3 inches wide. Nothing is visible. It's been going on about two weeks now. When nothing is touching it, it almost feels like a slight warming sensation. I can't stand to have even a sheet on it though. No other bodily signs of illness. Otherwise I feel fine. Any ideas????