Black Spots On Back, Itching. History Of High BP, Bipolar, Insomnia, Anxiety, High Cholesterol, Panic. Advice/

For about two years noe I have had what looked like black burn marks on my back only. At first I thought nothing of it since most of my life. Id have s back itch have one of my Kidd scratch it and it would stop instantaneously. But for about two years or better I have numerous black marks above my bra line. Right now one has turned into a sore with scabs around it. They now go as high as my hairpins and always itch like crazy. I am on several meds, but this concerns me like mad. I take; Subutex Clonazapam Lyrics Atenolol Potassium Elavil and Simvistatin. I am a 47yr old Black woman diagnosed with chronic pain: high blood pressure::bipolar: insomnia: anxiety; high cholesterol: and panic attacks. I know this is a lot but can you offer some advice as to why my back is covered with what looks like burn marks? I've consulted four me's to no avail.