Hi [DLMURL="http://www.ptsdforum.org/members/cragger65.html"]cragger65[/DLMURL],
Just a thought, but often those who say we can choose our thoughts and memories are also saying we are in control of them. Try to forget something you remember--it's impossible. In some ways, having control over our thoughts is like avoidance for one can avoid a painful feeling through distraction, but distraction does not remove the painful feeling. It just gives the illusion that we are in control. I suspect thoughts are similar. (I'm not saying distraction is not useful, it can be a life saver).
This person who told you this would have to also believe that those who can't control their thoughts are in some way defective. As a result, when we experience intrusive thoughts and memories we can then only criticise and judge ourselves.
I can see, however, where this person gets this idea from because many therapies teach this, however, many other therapies teach the opposite, e.g., Acceptance and Commitment Therapy, psychotherapy etc. So it's understandable that you're unsure about this as the world of therapy does not agree on this issue. CBT teaches that feelings/behaviour follow thoughts so change the thoughts and the feeling/behaviour will change. But, this too can give the illusion of control. CBT helps us to focus on alternative thoughts through asking ourselves questions, a refocusing to help us see a different way of viewing something. It doesn't ask us to stop/control a thought.
I hope I'm not being too "in my head," for I know your talking about something very painful.
All the best,
cec