Jess - you're 21 years old. You're a grown woman. "Too embarrassed to go to the doctor" is something it's time to get over. This is probably a rash of some kind, perhaps heading towards a more serious infection. It COULD be a very rare form of breast cancer - though given your age and the rarity of the diagnosis, it's unlikely. But you HAVE to see a doctor, given that this condition is progressing. Call your local hospital, and ask if there's a walk-in or outpatient clinic, and if there's a woman physician you could see; a woman would probably be easier for you to deal with. But no excuses - call the hospital or a doctor, and get the process going.  Action trumps worry/anxiety any day. So, as the Nike ads say - just do it. Take care - PJH