What Causes Itchy, Moderately Painful Rash In Pectoral Region?

Question : I have a itchy and sometimes moderately painful rash under my Pec's. I have had it occur a couple of times before under my left pec, but now it is under and on my sternum. The first time I had it, there was a pimple like blemish, that was somewhat painful. when it kind of came to a head, I popped it and continued to pop or drain it until it eventually went away. Although it is gone, it has left a small red spot where it was. It is a mass of tiny bumps, that when scratched hard enough, open up, but there is very little to no type of drainage.
This rash is very itchy and I have treated it with cortizone. If I leave it alone, it seems to go away quicker. Although it is topical, I worry that it is caused by an underlying problem below the skin.

The paragragh above was what I originally sent the Doctor. She responded, suggesting the problem might be a bacterial infection, possibly caused by a hair folicle. I'm not sure of how she exactly worded it, but she requested that I send a picture for further analysis. My question was closed out before I could send the picture, so I am sending it now. Actually, I don't see a place below to send a picture, so I am not sure what to do? I think it would be helpful to send a picture, so please instruct me as to how I could do that. Thank You