What Causes Uncontrollable Itching On Arms?

I have had uncontrollable itching on my arms for over a year or 2. usually on my left shoulder or outer surface of my upper arm. Once in awhile it will travel down to my forearm, but only the top of it, never under where the most sensitive skin is. Now it is primarily by the elbow and up to shoulder on left side, and my right forearm is covered with the little sores from scratching or even rubbing. I have gone without itching for days, but the bumps just keep coming, so i don t think my itching is causing it. The bumps are not red and they seem to be under the skin. you can not really see them, you can feel them, especially if I pull my skin tight. I live in Maine, and do get summer sun, but hate the cold, so I hibernate in the winter. I stay inside, and wear tank tops, because a shirt or anything touching it triggers the itch. This is of course worse at night. Like stings or bites under the skin. ESPECIALLY if I lay on either arm. I have been to a dermatologist and drs, They have no answers. Do Not Scratch is what they say. When I was pregnant 2 years ago, it got to be absolutely debilitating... I went days with just a cpl hours of sleep here and there, waking to wrap my arms in ice packs, and this would help until they warmed. I have used every topical cream I could find, bag balm (which helps heal current sores, but doesn t stop the bumps from appearing or the itch) I used rubbing alcohol for relief. but after a short while, I think that was irritating the skin even more so I stopped. I do use peroxide now every cpl days, just to keep infection away. Calamine lotion, no help. I can be a picker, but I have paid special attention to this, and it does not seem to be an issue, as I am hell bent on this healing so I refuse to touch it unless I have no option, and then I do my best to just rub quickly, and refocus. I tried changing laundry det. soaps, nothing helps. are there any suggestions?