Yes contact the 2 sites liz recommended. They will get you free care. Do not wait any longer.
As sumand said, you really cannot ignore a lump that size. I would go to the nearest ER and see what happens. After all, American hospitals treat indigents and illegal immigrants, so why not you? Luckily, we have "free" medical care in England, but we do pay a tax called National Health Insurance to the government through our salaries, so I don't believe it is free. The Susan Komen Foundation I believe provide free hospital care for breast cancer - look them up on their website. Also get in touch with the American Cancer Society and ask what free medical facilities are available to you.
You really MUST get your lump seen asap.
Take care,
Liz.
I typed "free MRI " i google's search bar and I found a tone of information. Try the link below.
http://www.freemedicinefoundation.com/application_form.html?gclid=CMe1zJza8owCFQGPWAodb1ZPCw
hope this helps
I am not sure where you live but where I live one of the hospitals, provides free MRIs which would be a start. I do not want to scare you but you have to get the situation investigated as soon as you can, I don't know what would you happen if you went to emergencyn for the pain in your right arm. My understanding is the hospital has to treat you whether you have insurance or not. Good luck , my prayers are with you. take care.