I Have Lumps Under The Skin On My Forearms--larger Than

I have lumps under the skin on my forearms--larger than a quarter, smaller than a silver dollar. They ITCH terribly to the point that I have scratched the skin off of my forearms in places. These are not insect bites. Went to a Dermatologist last week. Put 4 small cortisone shots in right forearm where lumps were and still are. The lumps near where the shots were injected, went away. Others stayed and this week my left arm began to itch. Again, lumps under the skin. I don't know what kind of MD to go to and I don't know what is causing this. Dermatologist said possibly this could have to do with my neck and nerves that could be pinched there??? What does this cost ? Any ideas? Gail