The symptoms that you are describing are associated with an anxiety disorder called Obsessive Compulsive Disorer. People commonly relate to the class labeled "reactive" where an actual trigger can be idenified as the cause of sid obsession and overt ritualistic behavior occurs as the person attempts to eliviate the anxiety, (i.e. obsessed with germs cause compulsive hand washing). Not so commonly known are cases where a person experiences "autogenous" or spontaneous obsessions. You may find yourself engaging in activitey to distract from these unwanted thoughts. For example, a person who suddenly becomes aware that they are thinking about murder might take on a huge cleaning project in an attempt to distract from the anxiety. There are a number of theories concerning that treatment approach and you might condier a therapist who is familiar with a few. I can tell you that the cause of your symptoms is more likely a disturbance in the cortial-striatal-thalmic reigons of your basal ganglia, than past life energy manifesting into this space/time continuum.
Why this has manifested in your brain is only conjuncture at this point. My information comes from a number of medical journals that I do not have handy. I do not recommend iddly searching the web becuase I have found SO MUCH condradicory information. Medical Journals are your best bet. Your local library or college might give you access. Sorry this is so long. Good Luck on your journey.