What Causes Pain In Chest Radiating To The Back?

I am 62 yrs old. I m a known case of Diabetes. I had my Lipid profile 1.5 month back and got a high LDL and cholesterol level. Since 3 months I was experiencing chest pain of moderate intensity with radiation towards back. I misunderstood it with gastric trouble and tried to relieve the causative factors myself. Then a week back I got severe chest pain with phogus like TIA (as elaborated by emergency doctor)which got relieved after 2 mins.+peripheral vessels(left arm+leg) no pulse with bruising of index finger which lasted for about 6 hrs. My Trop I leak was about 0.74 and my ECG showed IV conduction defect, non Q-wave ST segment elevation, defective T-wave with conclusion (Anteroseptal infarct). So how can I manage it through dietary and lifestyle modifications kindly tell me