Heart Rate in 50-60 rpm. Heart rate?

Hi I led a complete inactive lifestyle past 5-6 years(since COVID I am tied to home).Even I do very little household work due to my IT work.  Recent 2 years, I have had many health issues for which I consulted various dept doctors. Especially chest pain. ECG ECHO everything was normal( Doing regular annual health checkups). This health concern disturbed me and  my confidence a lot. I decided to lose weight from 85 kg. I did dieting( avoiding diary, oil, sugar and portion control on carbs) and lost about 12 kgs in 8 months. Still not much physical activity. But I notice my heart rate is around 50 s while sleeping and 50-60 while resting like sitting or lie down. Experienced shortness of breath, dizziness and nausea at times. Is it normal heart rate? Should I be concerned about anything here.