You also need to be aware of this very recent study:
http://www.jstage.jst.go.jp/article/circj/advpub/0/0809250096/_pdf
It is particularly relevant to your situation as a Type B dissection sufferer. ACEi drugs, taken at high enough dosages, are showing promise to people in your shoes. In this study, people taking ACEis after a Type B stabilized dissection had a 95% event free survival rate after 5 years ( I think 5 years) compared to the control group, which was around 64%. That is a big deal. I would discuss this with your cardiologist.
As far as the recent pain, get it CHECKED OUT NOW!!!!
You need to get these symptoms evaluated for sure. Talk with you cardiologist and or surgeon.
Please...do not watst time by coming to a board such as this to ask for the symptoms of something that could be potentially life threatning.
If you have the least bit of suspicion that you may have an aneurysm that is presenting any symptoms, go straight to your local emergency department!
As I am sure you are aware, a dissecting or ruptured aneurysm can lead to death, and it can happen quickly! Often a presenting symptom of an aneurysm can be back pain, depending on the location of the weakened vessel. Pulmonary embolisms can also present with back pain.
With your history, peace of mind alone would be worth a visit to the Emergency Department. There is no way to provide you with any reassurance that you do not
have an aneurysm or pulmnary embolism without adequate evaluation by medical professionals and that CAN NOT happen via an on line message board.
Don't take chances.