Since my pace maker battery has been changed , I now have headaches that are usually preceded by a tightness in my chest and brief shortness of breath. My battery had died but prior to the new one I had none of these systems. After the new battery, I had shortness of breath and cam close to a blackout when bending over and continual dizziness . The doctor said they failed to turn on a part of the battery that deals with rythm. That corrected the blackout and constant dizziness . Why am I now having headaches and tightness in my chest when I lay down to sleep. YYYY@YYYY