Do I have to pay german taxes on my US government disability pension and my retirement pension

If you are a permanent resident or Germany or are considered to be a German national, then the retirement pension IS subject to German taxes. The disability pension MAY be subject to German taxes, but possibly not. You would need to pose that question to a German tax expert.

If you are living in Germany on a temporary basis, then, by treaty, neither the pension nor the disability pension is subject to German taxes. They ARE subject to U.S. income taxes, however.