I, also, experience what you describe on a regular bases as well. I spoke to a doctor about it and she told me that it was just my way of dealing with my anxiety disorder. (Alas, I'm not diagnosing here or anything. Just sharing what my doctor told me.) But then again, due to money issues I had to stop seeing my doctor so I was never fully treated for it. I personally believe that it may be a way or dealing with anxiety or bad experiences. Like you, mine was also brought on by a bad drug use. The only time I've ever felt relief for it was when I went through a bad time in my life and shut down emotional. (IE: Repressing everything. Which is also not a good way to deal with things.) But we are all different and my experience is different from yours and the way I respond to things is different then the way you may respond to things. But if you feel the way I feel on an almost daily bases I would suggest seeking out professional help.