Is it normal that i feel an itching sensation in my chest?

For a long time I've felt this very uncomfortable itchy sensation under my skin on my chest between my breasts. Basically my cleavage area. It is very uncomfortable and comes and goes. Usually it comes when I think about it and can last weeks if not months, and leaves when I forget to scratch. Nonetheless, it worries me. I can only describe it as a heart itch. I get temporary relief by cracking my back. I'm also overweight and have been my whole life but am relatively healthy ( no diabetes, heart problems, or high blood pressure). What could this be? I'm scratching my chest raw! :(