Have done chemo and am doing herceptin (trastuzumab) for breast cancer. have backache between shoulder blades and neck. herceptin (trastuzumab) or could the cancer be back?

It isn't due to Herc: Pain between the shoulder blades can be caused by any number of reasons/causes including muscle pull or sprain. It is not likely to be due to herceptin (trastuzumab). So make sure that your oncologist is aware of this development and may consider checking you for any recurrence of your cancer in the bones(spine and or ribs). This can be determined with a bone scan or another imaging test.

I'd bet neupogen: But check your oncologist, it could be either. Details of breast cancer (tnm, other receptors) i only know you are her-2-neu + by use of trastuzumab. Talk to your doctor before jumping to conclusions.