I know enough to know that my backpain was not a symptom of a heart attack, so no ER needed.
I did have an MRI scan and investigated by a Neurologist and Orthopedic surgeon who assessed it. Nothing abnormal was found.
I stumbled on the cause via a Naturopath who suggested it was a Vitamin D deficiency. This had not been tested before that point and which I though was a rather fanciful idea, but true nonetheless when I had a 25-hydroxy vitamin D blood test.
Supplemental Vitamin D3 of 20,000 ius per day eradicated the problem within a week.