When I first started having panic attacks it was obvious that anxiety was causing them. But it was not obvious what was causing the anxiety, I still don't know but have gotten used to everyday life and the things that are the stresses. There are sure to be some things that cause higher levels of stress, obvious things are driving, walking in crowds, heights, loud noises as these things can be stressful for anybody, being somebody with ptsd you are even more prone to panic in these situations.
There are probably triggers that are related to trauma that might be well hidden, pay close attention as you go through life to figure out what these are but also know that everyday things may seem to be triggers, because you have ptsd these everyday things are triggers also. Through healthy exposure you will get used to it while learning to avoid things that might re-traumatize you.