See Robert Bruce's book "Psychic Self Defense".
Separately, there was a doctor (MD) about a century ago, who wrote a book detailing his multiple experiences with patient "spirit attachments" . These were almost always "dead personalities" that were clinging and inhabiting living people and causing problems. What is interesting here was his technique ... he would hook them up with a Tesla coil (you know, as in the movies or Tesla himself, where the person is touching a metal charged ball and lighting is flying off their heads .... something like this http://www.youtube.com/watch?v=Zi4kXgDB ... re=related
) and it would knock the loose ghosty-spirit right out of the patient. (The ghost thing, shocked, would look for a fresh place to land, which turned out to be the doc's wife, a medium of sorts). If I can remember the name of the Doc or his book, I will add it in here later ... it's been about a decade since my visit with it.
But if you have a local science museum that has an interactive unit, you might get a chance at a coil. Careful about DIY, there are risks if you ground out etc. Lots of youtube and other stuff on the net about that. Not sure it's what you need, but it came to mind.
Separately, you might just stop by the (regular) doctor's office and make sure that you don't have some medical issue going, enlarged heart, heart blockage, etc.... the symptoms you state are consistent with those problems.