What Causes Constant Pain In Armpit And Neck?

im 22 and just had a CT scan/ chest xray, blood work, because the last six months i have been having constant 24/7 pain in my armpit and neck. the pain increased from tolarable to not. i now have sharp pains in my breast throughout the day. i am extremely concerned about breast cancer as my mother is a breast cancer survivor. can my mind be put to rest knowing that the CT scan came back normal or should i further investigate this pain