Pain inside upper arm with tingling

For the last couple years I have had an annoyance under my arm when I lie down and rest my arm on my side. Feels like my sleeve or sheet is bunched under my arm but, it isn't.
Now the last month that area is painful and I am having tingling and crawling sensations all up and down my arm along with weakness.
At times it is almost impossible to get comfortable. Having fibromyalgia doesn't help this discomfort.
I have recently had an xray of my left shoulder because we have been thinking it could be a nerve pinch but, that was before I realized that the pain actually originates under the arm and not in the shoulder.
Cancer runs strong in both sides of my family. All types from breast to brain to skin and lungs.
I am very nervous as to me this feels like what my childhood pet went through with a tumor squeezing off circulation and blood flow.
And I'm still waiting to hear about the xray I had over a week ago and wont be SEEING my doctor for another month and a half. (free clinic drawback)
Is it possible this is cancer related? If so, what kind could it be? I would like to go into my doctor with the right questions to ask.
Any help is truly appreciated.
thank you

[tinglingulnar]

I have had a long rooted pre-cancerous mole removed when I was in elementary school too, so I myself also have a history, not just my family members. If this helps.