The problem is that when I go to bed and lie down I start to have a tightness in my chest and become breathless if I get back up and sit up it improves last night it was several hours before I could return to bed. My health history is I have had three heart attacks and have a triple a
I would request you to visit your cardiologist.  The symptoms you describe is called orthopnea, which is seen when heart pumping is weak, and It's unable to pump handle the extra blood coming in supine position from the legs due to elimination of gravity.  If you also have swelling generally in the evening or so.  You need to be put on a diuretic for handling the extra fluid.  Your cardiologist your be able to guide you with the relevant investigation and optimization of treatment.  Till than I would request you to sleep with 45 bed elevation at head end, and restrict fluids to less than 1 liter a day.  Regards Chat Doctor.  For further assistance you may contact me on Chat Doctor through Http