Hi , There is a bruise-like pain in the middle of my upper thigh , and i don't know what it is. I am on a dance team, and we do a lot with our legs , so I think I may have strained it , but I am not sure. There is no mark , but when I put my leg up or sit a certain way , or touch it mildly , it hurts. Can you explain this to me , and what I can do to help it heal?