I feel sometimes fast heart beat for 2-5 sec it the feeling is something weird can't explain how it feels I guess it is called premature or skipped beat.(Mostly at night) And feel like sudden neck or breath or beat spick don't know what it is. I have done 3-4 ECG and 2d echo and tmt and lipid profile test all also for checking electrical signal I didi MRI of brain and neck all came normal and sometimes chest pain pinching pain and discomfort type feeling  hand and shoulder pain it came and go for sometime but it happens and sometimes breath loss feeling mostly at night. Sometimes chest tightness Currently I am taking gastric tablet since 3 weeks What can be reason