Thanks for posting your query.
You said you got an ECG done but you have not mentioned the report. Since you have chest pain
and back pain
from 6 years this seems to be musculoskelital pain.
Cardiac chest pain will be very severe and will be associated with ECG changes. This is also associated with sweating and palpitations.
Since it seems to be musculoskelital pain you can try analgesics and if needed you can get a chest and spine X ray
Hope i have answered your query.
Thanks, and regards.