Agreed. 400 mg of test a week is more than double my TRT. In fact, it is more test than I have taken on any blast in the last five years.
You may need a deload based off the lack of motivation, but the back and rib cage it sounds more like an injury to me. The good thing is that it would be a minor injury, because if it wasn't you would definitely know in that region. It would be pretty difficult to lift at all. Might want to throw the kitchen sink at it since it has been nagging you for a couple weeks, i.e. anti-inflammatories, red light therapy, deep tissue massage, heating pad (often), chiropractor and a little rest.