For the past 2 months, I have been getting tightness across my chest , strange pulsating sensation in my head, stiff neck , ringing in ears, if I stand in one spot too long i feel like i am going to collapse. I have a pacemaker and it was checked recently with nothing abnormal except for a few episodes. I am packing about 1% of the time in my upper chamber I believe. I have never felt this bad before...