I'm a healthy 28 year old male with no history of any lump issues. For slightly over a month now I've had a red lump under my arm. That alone isn't the alarming thing. What is getting to me is that it seems to drift around. It will be a raised red lump one day, then seem deflated, then gone. A few days later, it will have shifted locations and be raised again. it's not very large, about the diameter of a pencil eraser and raise only about the height of a regular small zit. But it does hurt, and it seems to leave a trail when it moves not unlike a stretch mark. I'm really concerned, and have not seen a dermatologist.