Breast lump & thickening...now have sore arm?

I was referred to the breast clinic last week as have a thickening at right side of my breast and a lump underneath my nipple....this morning my arm is sore...almost like when you get a 'dead arm' feeling...pain from shoulder to finger tips....anxiety is through the roof!

Do you think it's just because of the poking and prodding or something I should be worried about?

Any advice much appreciated xx