Armpit Pain

I have been experiencing a discomfort under my right arm, but it is now progressing into my upper right arm (underneath) and down to my ribs.  

I originally thought it was a discomfort because of the bra I was wearing but the discomfort is constant and has been going on for abou 2 weeks.

I hate going to the doctor for something that may turn out to be nothing and then the insurance won't cover any of the tests.

[Cleveland Clinic]

Dear Giraffe504, Over the internet without ability to evaluate including physical examination it is impossible to determine what the source of your discomfort is related to.  

Your doctor would be better able to evaluate based on questioning and physical examination.