1 year post op of Bilateral Mastectomy, I started to have back pain. Is this normal?

Please make sure that you contact your oncologist and breast surgeon immediately for a detailed work up. 

I would recommend a full work up by your breast surgeon and oncologist. I would do this as soon as possible as pain can be as simple as a muscle spasm or indicate a more serious condition.

I think that you should see your breast surgeon to be properly evaluated. You may need to see your oncologist or internist as well to rule out causes of the pain.

The best course of action with progressive pain would be to see your breast cancer surgeon and see if you need to have some imaging and/or other tests to try and pinpoint the cause of this pain. The hope is that it is just maybe muscle pain that could be addressed with massage and stretching but you really need to see your breast surgeon to ensure this is not related to your past cancer history.

I agree, given the severity of the pain, I would recommend that you have a full workup/xray/scan to make sure that there are not any metastases.

With pain severe enough to  require pain meds you need to be worked up full for bone or spine problems. One must make sure there is no bone metastasis